TSA-style body scanners are coming to public spaces | Hacker News Reader

TSA-style body scanners are coming to public spaces

massprivatei.blogspot.com

237 pointsJerry2177 comments

Millimeter-wave machines at airports today are totally and completely useless. Germany's transportation administration reported a 54% false positive rate for these pieces of rubbish. You are better off randomly searching people by flipping a coin.

These are multi-million dollar security theater failures and it bothers me more that people are considering buying even more derivatives based on this garbage technology for anything.

Police officers or security guards could just literally point one at anyone they find suspicious and use it to justify an illegal search, because it will most likely read yes, even if the person's pockets are totally empty.

Having a high false positive rate isn't really the end of the world for security screening though, as long as they have a low false negative rate, which I don't see many articles complaining. Even at 50% false positive rate, it's 50% time saved compared to patting down every one. Additionally, these machines highlight potential areas to search more carefully, so there's probably even more time saved there.

If your antivirus or car alarm start flooding you with fake warnings you will ignore then more often than not. It’s human nature and you can’t really change it without some drastic measures like severe punishment or constant checks to keep people on their toes. And this last one just kicks the ball further up the ladder but still to a human with the same predisposition.

> Millimeter-wave machines at airports today are totally and completely useless. Germany's transportation administration reported a 54% false positive rate for these pieces of rubbish. You are better off randomly searching people by flipping a coin.

Edit: note that it seems I had a wrong understanding of the term false positive rate, ignore this comment.

Statistics doesn't work like that. The false positive rate is pretty meaningless in this context. It only determines how much useless manual work is performed after the machine flags you incorrectly.

You should look at the false negative rate in order to determine how much of a security plus they bring.

That being said, I think the whole airport theater is ridicolous. If terrorists wanted to kill people, they literally have thousands of alternative ways to achieve that.

In this context of using them in public spaces it’s the false positive that matters most. The complaint is that the machines basically always alarm, which means the only thing they can be used for is making up a bogus excuse to manually search / harass someone based on no real suspicion.

But they don't always alarm according to the number that was presented. It alarms twice as many times as it should. That's not good and I certainly wouldn't want these in public spaces.

But you can't just look at the false positive rate and how much more work and unpleasant/unnecessary searches they cause. You have to take into account the false negative rate to get a complete picture. Manufacturers and the people who want these machines will always err on the side of too many false positives than too many false negatives.

Again, I personally think that these machines have no place in public spaces, no matter their hit/miss-rate.

> It alarms twice as many times as it should.

That's not what a false positive rate is. It alarms on half of everyone that goes through. It's utter garbage as a first-line test.

I think this is a misunderstanding. From Wikipedia [1]:

> A false positive error, or in short a false positive, commonly called a "false alarm", is a result that indicates a given condition exists, when it does not.

So a 50% false positive means also that in 50% of alarms the condition was actually true.

What you mean is a 50% alarm/trigger rate. Which, depending on how many people do have something on them that should trigger the alarm, would result in a far far higher false positive rate.

1: https://en.wikipedia.org/wiki/False_positives_and_false_nega...

> What you mean is a 50% alarm/trigger rate.

No I don't. It's just that the true positive rate is close enough to zero that both false positive and alarm rate are roughly the same number.

Nevertheless you're still not understanding "false positive" correctly. If you correctly pick 5 out of 100 true positives without any flaws, and also have a 54% false positive rate, you're grabbing 51 false positives, and >90% of your picks were incorrect.

And I'm pretty sure the true positive rate is well under 5% to start with, which just makes it worse.

"In Germany, the false positive rate was 54 percent, meaning that every other person who went through the scanner had to undergo at least a limited pat-down that found nothing."

This is wrong. Even your quote shows this. A false positive rate is how often it triggers when the true result is false.

> A false positive error, or in short a false positive, commonly called a "false alarm", is a result that indicates a given condition exists, when it does not.

So 50% false positive rate means 50% of people who should not be flagged are flagged.

https://en.wikipedia.org/wiki/False_positive_rate

It is quite definitly true that every second person needs to be patted down without a reason, purely on my personal experience as a frequent flyer

Not quite true. A high false positive rate leads the people running the machines to stop reacting seriously to alerts, which means that they don’t do the manual checks with as much care. This is even more of an issue when everyone in line knows they are bullshit and has no respect for the people running them.

A false positive rate of close to 50% means that every second alert indeed pointed at something real. That should not cause the staff to get unmotivated. Again, without the false negative rate we can't judge if they are complete bullshit or not. If it were a 90% false positive rate then sure, that would clearly have the effects you outlined. I don't think at around 50% that's the case yet.

> A false positive rate of close to 50% means that every second alert indeed pointed at something real.

No it doesn't.

Please see my other comment which references the definition of false positive rate because I think your understanding of the term is wrong. You have a 50% alarm/trigger rate in mind. And please try to reply with a bit more substance than "No".

To quote an article on the subject: "meaning that every other person who went through the scanner had to undergo at least a limited pat-down that found nothing"

> And please try to reply with a bit more substance than "No".

Eh. I was hoping you'd just delete the comment rather than have two parallel arguments.

> The false positive rate is calculated as the ratio between the number of negative events wrongly categorized as positive (false positives) and the total number of actual negative events (regardless of classification).

https://en.m.wikipedia.org/wiki/False_positive_rate

54% FPR means half of all people who aren't trying to bring anything illegal onto the plane gets stopped.

Since basically nobody are actually trying to do this, that also means that more than half of all people going through gets stopped.

The ratio of true positives to positives must thus also be vanishingly small.

No, it means that about 50% of people scanned would trigger a "positive". The false positive rate is the number of false positives divided by the number of actual negatives.

100 people, 50 false alarms, 1 actual problem alerted and 49 marked as safe correctly = 50/(50+49) = ~50%.

That's just wrong. This is ML 101

False positive = (Machine says positive but grand truth is negative) / (Machine says is positive)

In English, a false positive is when the machine declares something as positive but it is actually negative.

This fits a sanity test because ~50% of people that pass through a detector do not get patted down. The truth is closer to 10%. Even then, a true positive probably includes someone with two pennies in their pocket.

https://en.m.wikipedia.org/wiki/False_positive_rate

In statistics and ML it’s (FP) / (FP + TN) aka (false positives) / (actual negatives samples). This is by far the most common definition.

Here ML using the common definition see fall-out: https://en.m.wikipedia.org/wiki/Precision_and_recall

You are right this is ML 101, but you are wrong. Someone else has linked the wiki page, and I've posted it elsewhere and I would strongly recommend you read it as your interpretation is very incorrect.

> In English, a false positive is when the machine declares something as positive but it is actually negative.

Yes, and the rate is based on the frequency this happens in your negative set.

>This fits a sanity test because ~50% of people that pass through a detector do not get patted down.

The 50% figure may be wrong, but my definition of what a false positive rate is not.

You're thinking of FDR: False discovery rate. It equals Σ False positive/Σ Predicted condition positive.

See https://en.m.wikipedia.org/wiki/Precision_and_recall for a table of different terms.

Wow, that definition is counter-intuitive. Ive expected the false-positive-rate to be the number of false positives divided by the number of all positives. Isn't it how "rates" are usually defined? No wonder everybody is confused.

I think it's a perspective thing. You are looking at the rate of false results, so given a particular type of input what rate do you get it right? For negative ground truth your possible outputs are "false (positive)" and "true (negative)".

I agree it can be confusing, but I think people would also make the opposite mistake if it were defined differently.

You're thinking of FDR: False discovery rate. It equals Σ False positive/Σ Predicted condition positive.

See https://en.m.wikipedia.org/wiki/Precision_and_recall for a table of different terms.

This is what they do in Mexico when entering the country from the perspective of flipping a coin. I took my vacation in Maya Riveria and upon entering the country they have a box with a button. You push the button and it lights up green or red. Green means you go, red means you have some additional security checks.

I wonder how well a tool would work that anonymises people - so those with power won't consciously, or subconciously, target people with brown skin and large beards - while still showing how they are behaving. You could even use cameras to monitor heartbeat [0] and body temperature.

[0] https://techcrunch.com/2016/12/05/oxehealth-uses-cameras-to-...

Not to mention the culture of suspicion and insecurity it builds up. It's insane, and terrible for democracy.

Having just gone through the airport yesterday I definitely relate to this.

Even when walking through security totally clean you feel helpless, it is probably the closest we come to feeling the pressure of a totalitarian govt. in the USA, it makes me appreciate the bill of rights and not take for granted what it gives us.

Back when they originally came out, I'm sure you'll recall that the operator was basically looking at a high resolution nude image of the person being scanned. The false positives came when people protested and they changed the display to a pixelated cartoon that shows "suspicious" areas as illuminated squares that need to be patted down by a human.

No, those are two totally different technologies. One was x-ray (and terribly dangerous to use in that way) and the current in millimeter wave (which literally cannot make a nude image. The best it can do is the cartoon outline)

This article is possibly where the poster above me read the 54% FP statistic, and its point is not about resolution but that the different wavelength of energy used will show things like sweat as surface, and combined with the automated detection it produces a lot of false positives.

https://www.propublica.org/article/sweating-bullets-body-sca...

In the context of an administrative search at the airport, security guards can already just search whomever. Arguably, the machines are able to clear ~50% of travelers and exempt them from a more intrusive search.

My wife can't go through these scanners, as she has a medical device that the device manufacturer has warned have not been certified to go through them, and will not be liable if the device stops working (which in this case would mean she dies.)

At the airport, she always has to opt-out and get a pat-down (or did, until she broke down and paid the brib...err, "fee" for pre-check.)

Will she be safe walking around areas that use these scanners? Will the users of the scanners be required to announce that they are in use? Will there be an opt-out process? How would that even work in a public space? If she opts-out, is she going to end up getting felt-up by some untrained minimum wage pervert with a power complex? Who is liable (legally and financially) if her device stops working because someone made her go through a scanner without her knowledge or consent?

This is bullshit for so many more reasons that surveillance (though that is also important.) This is literally a life or death concern for us.

Without information regarding the medical device, it can be difficult for us to provide a solution, so in my opinion you should ask yourself:

* What properties cause the device to malfunction?

* What kinds of scanners/tools can lead to the malfunction?

* What would the malfunction look like?

* How much time would she have to get medical support?

* Is there an alternative medical device that decreases the risk?

* Is it possible to get a medical certificate that shows she has the device and its implications, allowing the officer to know before-hand?

It is worth noting that some devices that can cause the malfunction may already be available for private citizens to purchase, so creating a plan of action may be the best option regardless of whether reinforcement officers intend to use it.

I apologise in advance that this comment has nothing to do with the posted article, and is instead to do with the use of HN.

After dang's comment on the latest Assange thread to make the first page on HN, I am trying to decide whether the posted article is one that stimulates intellectual curiosity, or indignation and repetition.

I think the answer is - probably the latter. We're not likely to learn much new knowledge from it and it's more likely to generate forceful arguments than productive conversation.

Are postings like this welcome on HN or merely tolerated? I assumed, because politically controversial posts frequently make it to the first page, that they are acceptable and welcome. I am not so sure anymore.

I believe that an active mind is a politically engaged mind - but perhaps HN is just not the right place for political conversation. I enjoy the civility and dignity of the best threads on HN- and I have to admit that the majority of them are not political. It's hard to have a level-headed, sober discussion on political matters, when everyone who has political views tends to have _strong_ political views (I sure do).

So I don't know. Maybe posting stuff like this on HN is not such a good idea after all?

(With apologies to jerry2 who posted this article)

I'm more concerned that conspiratorial content and clickbait bullshit is becoming king on HN. This site and the general writing/editorial style fires off massive warning sirens and when I tried to look up the site further, most of the links that followed were similar conspiracy sites.

Now don't get me wrong, this is separate from the issue of privacy and ensuring that the government doesn't overstep its bounds. We shouldn't be lured in by people using that as a wedge to spread FUD. Just read the comments on the article by the same writer to understand why.

I'm genuinely curious: do you believe this post in particular to be controversial? I can't picture many people (I can picture some) who would think be in favor of what is described here.

With any sentence that contains a "can't think of people who X" structure, you should realise that people you know and talk to are people who think like you. Exceptions don't break the rule, as always – if you do make a statement like that think first if your sample is representative of the population.

I think a simple rule is this: if the topic has to do with the balance of liberty and security, it's going to be controversial.

But not necessarily because there's true dissenters in the simplified binary "you're with us or against us" way. But because it's a topic with no objectively right choice. Liberty is genuinely important. Security is too. Society and Government is largely about the balance of those two.

The issue is not about whether people "favor" the opion of the author or not, it is about whether the article meets the HN guidelines [1].

[1]: https://news.ycombinator.com/newsguidelines.html

Yes, I do. I think the fact that there is a very strong opinion for or against a political opinion makes it controversial, by definition. In effect, it means that any discussion on the subject is going to be charged and unbalanced. The more people are on one side of the debate, the more so.

This is perhaps why articles on, say, vaccine denialism or climate denialism and other strongly politicised subjects like that are not well received on HN. On the one hand there are very strong views around them, on the other hand it's very clear what those views are and where they come from after years of these "debates" raging online and there's really nothing to see there anymore.

Scientific controversy of course is another matter. That comes down to robust debate between experts from which everyone has a lot to learn. That sort of article is also commonly flagged on HN, which I think is unfortunate.

Anyway, I've contributed plenty of politically controversial articles myself in the past, and contributed to such discussions. Maybe I was wrong to do that. I don't know if there is a place on the internet where I would feel more comfortable than on HN to have such discussions- but maybe HN is still, just, not the right place for them. Edit: maybe, if we keep having more and more of those conversations on HN it will stop being the place where I feel comfortable having them.

But is your concern about controversy in this community or in general? HN substantially leans left/progressive (note that I did not say it was universally so). There are any number of articles posted here that take that view such as what to do about climate change, wealth, and speech. While these stories certainly get some long threads where that minority that isn't of the HN popular mindset go back and forth with those that are, by user counts these articles are not so controversial here as they would be across the broader public (remember, these are generalities that I am speaking in).

So should the general HN group tendencies be considered in what's considered controversial vs. what is just informative? Should the community focus on discussions in areas of climate, wealth, race, sex, etc. be limited only to the implementation details of the generally accepted HN point of view?

I do get what you're talking about. While I agree in with the premise of the parent story, the article is clearly written to charge emotions moreso that present rational arguments: I hate that bullshit. Personally, I'd prefer to be a member of a ruthlessly "on-topic" professional technology community where progressives, conservatives, etc. are expected to save their politics for Facebook or Twitter and provide input on those topics for which they are best qualified. Maybe it's too much to ask, though, because I ain't found such a forum yet.

HN has a small amount of absolutely brilliant content/commentary that I've not found elsewhere, as well as a larger dose of just OK content/commentary... which keeps me coming back... which comes with a large portion of utter crap which just becomes a big shit-show, and shows that this community of STEM types which, frankly, likes to see itself as superior to the less enlightened, broader public, really isn't any better at formulating ideas than that public in areas outside their specific specialties. Oh, sure, the better education means the quality of writing and rhetorical flare is also better... but that doesn't mean that the actual ideas are less emotionally driven or more well considered: just that the rationalizations are more nuanced than they might otherwise be.

OK, stepping off the soap box. I will say, for my part, I use to get much more caught up in the political discussions here and was wrong to do so. I've stopped that bad behavior for the most part: I wasn't helping, I wasn't changing minds, I was simply eroding the professional demeanor of the community.

>> But is your concern about controversy in this community or in general?

About this community in particular.

I agree. If an article doesn't meet the guidelines [1], then please don't upvote it.

[1]: https://news.ycombinator.com/newsguidelines.html

The topic of the article is interesting, as it highlights a particular trend in technology and raises a lot of stimulating questions. But upon reading the article itself, I find that it's very political in nature and uses emotive kind of speech. It provides very little actual information beyond the title. Personally, I think the article is a waste of time and I'm actually shocked that it received so many upvotes.

Not everyone has the luxury to ignore news and politics. Sometimes these events touch our lives in ways that a new release of the Rust compiler could never.

(Not to pick on Rust, I love the language, but just an example)

I agree this site should not turn into Reddit, or Digg. What keeps HN great is the highly technical discussion around these topics. On mainstream articles like this I often skip reading the article, and go right to the HN comments to learn real info about the topic.

We have a community of some extremely smart people, let's not filter the articles posted, but instead harbor the intellectual conversation around the articles, because I think that's the real value of this site.

I agree with this, and will add:

Not everyone will see every thread on a topic. Some may only see a TSA thread on HN once a month or quarter, if they're a light user.

The repetition is indicative of the community's feeling a topic is important. And that's what people come here for. To see what this community thinks is important.

I don't like it, and maybe HN is not best suited, but it is relevant. Sharing such news is the only way of taking the pulse of how authorities perceive technology. Police using AI and visual recognition, investigations of social media accounts, drones starting to be used in cities. The only reason this feels like "repetition" is because we don't seem to be able to do anything about it, but discuss it as it unravels.

Is this company for real?

Lots of executives. Lots of advisors. High powered board. No demo. First prototype due this month.

Uh oh.

The Lincoln Labs group didn't get very far. They could image a single mannequin at close range in a controlled environment. Whether this will work in a cluttered environment is an open question.

It might work for sports stadiums, which heavily restrict what you can bring in.

The point is that the idea of public millimeter wave surveillance has some amount of public support.

Even if they deploy an ineffective version in 12 months, in 240 months they might have effective hardware. This is the direction some people want things to go.

> Even if they deploy an ineffective version in 12 months, in 240 months they might have effective hardware.

Provided they can still borrow money to fund operations.

cough Uber.

> The point is that the idea of public millimeter wave surveillance has some amount of public support.

Does it? If anyone has data on this, I'd be very interested.

I've recently been giving some thought to pervasive electronic and video surveillance as an alternative (specifically not as a supplement) to the presence of armed police being deployed by default in public.

This is what it's really about. If you talk to police, they don't want to invade people's privacy. The push is coming from some tech company pushing a product to siphon the taxpayer. Politicians want to make a buck too, so they approve it because no politician ever got fired for pushing too much security on the public.

> Is this company for real?

> Lots of executives. Lots of advisors. High powered board. No demo. First prototype due this month.

> Uh oh.

It's like reading Bad Blood in real time.

I was thinking uBeam.[1] Remember uBeam - wireless charging via ultrasonic audio? They've been hyping that since 2011. Was supposed to ship in 2015. CEO replaced last year.[2] Disappointing demo at CES 2019 - they can light up a LED at 1m range.[3]

[1] https://techcrunch.com/2015/04/26/kill-the-cord/

[2] https://techcrunch.com/2018/09/20/ubeam/

[3] https://liesandstartuppr.blogspot.com/2019/01/more-ubeam-at-...

First thing that comes to mind is, are these scanners safe – i.e., do they have any kind of active radio wave source? How reliable are they? Can they malfunction and emit harmful radiation? Is it health certified for kids, adults and pets? What about medical safety devices? Is there a stringent regulatory body certifying these?

Second, how does law enforcement of the normal kind work in a society vs how does terrorism prevention work? For the later, intelligence gathering/sourcing, infiltration etc. - isn't this the only realistic (scalable) way for it work? If terror prevention becomes part of law enforcement job, then we will end up with a police state that is unlivable (in effect, terror is now perpetrated by state!)

Now, is this scanner device to be installed in public places – is it for law enforcement or for terror prevention? If the day-to-day life habits require this level of monitoring for law enforcement, then that society is screwed up beyond repair.

Btw, in my country we have X-ray for bags and metal scanner for body in every hotel, mall, theater, public transport hub, offices etc. There's usually a security guard who will wave a wand on your body but doesn't really know how to use it. For vehicles they make you open the trunk and boot and visually inspect as well as look underneath with a mirror. But I have not seen any 'positive' (false or otherwise) catch.

In movie theaters, the best I have seen them catch and confiscate is outside food (for commercial policy reasons, not security) and cigarette lighters (for fire safety and smoking ban).

It was irritating at first, but now everyone has become numb to it and you just go through the motions.

none of the safety concerns will matter, if the bribes are big enough. Politicians will be exempt.

> are these scanners safe – i.e., do they have any kind of active radio wave source?

These two things are unrelated unless you are transmitting kilowatts of power and things become heated. Yes, there is a regulatory body (FCC) that limits emissions such that the volts per meter gradient is below some given threshold for a frequency range. And the higher the frequency the higher the power is needed to achieve the same v/m.

The 'war on terror' has very little to do with terrorism itself or preventing it. It's all about means to monitor and control the citizens of a nation.

As for large scale public 'scanners' well, they have been deployed in the USA around events like the superbowl. I recall they used to call them 'viper' squads or something. And in those I recall they were using backscatter x-ray vans, something which is not intrinsically safe due to using ionizing radiation (unlike radio).

I'm not a huge fan of "only the government gets weapons". It's technologies like this that are bothersome because of both 2nd and 4th amendment reasons.

While I respect your personal taste and a wish for additional perceived safety there, the data says it‘s probably a bad idea. Just carrying a gun will make you 4.46 times as likely to get shot [1] and increase the likelyhood of all loved ones around you to get hurt as well.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2759797/

No one was bitten by a shark who never entered the water either. There is more to the gun control debates than single-input statistics like the one you cited.

I'm not sure I follow this analogy, unless you're supporting their position?

I too found the analogy interesting. I think the idea is whether or not to "outlaw" the water where the shark swims.

Actually, no, study after study shows that the amount of guns in a society is strongly correlated to its homicide rate, both directly as well as indirectly (i.e. more violent police raids because they assume residents to be armed).

Taking your shark tank metaphor, some people believe it‘s simply not possible to remove guns from a society, which is untrue as well, as the recent example of Australia shows.

Heck, lots of people in Germany used to have a gun in WW2, while in 2011, German police shot a whole of 85 bullets in total. Which, incidentally, is exactly one bullet less than Texan police emptied into a single, unarmed suspect after a car chase in the same year. Well, you get what you vote for.

Switzerland has a very high gun ownership rate and yet a very low homicide rate. It turns out that it’s complex, like every other political issue.

I am neutral / undecided on the gun ownership issue but simplifying and using misleading information doesn’t help anyone.

Right, but Switzerland still has the draft, and consequently more awareness about gun safety among owners, as well as inflated gun ownership statistics because you are required to take your gun home with you. And while guns are relatively easy to buy, ammunition is much more controlled.

Switzerland also has a lot more social security than the US. I agree that it's more complex than "guns are bad", but using Switzerland as an argument for gun ownership is just glossing over the details to come up with an artificial example where gun ownership doesn't result in increased violence.

> come up with an artificial example where gun ownership doesn't result in increased violence.

Though I do not concede the use of the word "artificial" as correct in your sentence, bringing in the Swiss data point is incredibly relevant in response to a claim that "Actually, no, study after study shows that the amount of guns in a society is strongly correlated to its homicide rate, both directly as well as indirectly."

Could it be that people there are simply more responsible/comfortable in life in many ways that US etc citizens are not?

Some of the things you said are neither here nor there. You shouldn't just mention a random police shooting (note: unarmed != unjustified) or allegations of voter irresponsibility without describing how that supports your claims.

Not entirely true.

>"A fisherman was attacked by a shark after he hauled it into his boat to pose for a commemorative picture.

>Angler Stephen Perkins, 52, got more than he bargained for when he hauled the fish on board his boat 'Serenity' off Lundy Island, Devon.

>As he was preparing to unhook the fish, it sank its teeth into his wrist leaving him needing re-constructive surgery. It has earned him an unlikely place in history as the first documented case of a man being bitten by a Blue Shark off British waters."

And if we include dead sharks -

>"There have, however, been several people injured by sharks on land including a landlady in Kent who was hit by a set of shark jaws which fell off the wall of her pub and a man whose arm was trapped inside the jaws of a dead shark he was transporting on ice after he stopped his van suddenly sending the carcass flying through the air, snapping its jaws shut on his arm."

https://www.telegraph.co.uk/news/earth/earthnews/3350690/Man...

I suppose that this goes to prove the GP's argument?

This is honestly one of the most hilarious counter-examples I've ever read.

>I suppose that this goes to prove the GP's argument?

Nahh, if I was doing that I'd probably have pointed out that per capita, people are twice as likely to be shot to death by a toddler in the US as by a cop in the UK.

I was merely taking the golden opportunity to be very silly about sharks.

Well, it worked, I guess?

Have you just had those waiting around for the perfect moment or did you just go out and find them?

A little bit of column A and a little bit of column B. I had a vague memory of some guy getting bitten in a boat, then added google.

The people who have toddlers and don't use high shelves with no crawl-up access, or something to shove toward the shelf to crawl up to it, should be shot and killed by toddlers.

Say hello to Darwin for me.

All very well, however really a lot of the people shot are kids, random visitors, the toddler themselves or other toddlers. Toddlers don't tend to go hunt down the legal owner to enact some sort of darwinian karma, weirdly enough.

Interesting paper. My first thought was that it would be impossible to distinguish causation from correlation, but it looks like they definitely tried. That is, how do you account for the fact that "people want to kill you" increases both the likelihood carrying a gun and of being shot. In Pearl's terminology, have they really calculated the effect of do(gun) instead of just (gun)?

Skimming the paper, it looks like they paired shooting victims with demographically similar control subjects. While the overall conclusion seems plausible (gun possession causes an increase rather than decrease in risk of being shot) this approach seems really hard to do correctly. Are you familiar enough with their methodology (and with the causative pitfalls involved) to discuss it?

This research doesn't account for most defensive firearms use, in which the gun isn't actually fired, but is "brandished" to deter the threat. When defined correctly, defensive gun use is actually several times greater than negligent discharges, assaults, homicides, and even suicides by gun combined.

Anecdata: I was talking to a cousin of mine at a family reunion. He carries a handgun (legally) and is familiar with the proper use and handling of guns.[1] He told me that he had only ever had to draw his gun twice (gun held at the side pointed down at the ground, not raised, not aimed) and that was enough to calm the situations down. I could see his relief.

I don't know how much statistics can help with decisions (like "Should I own a gun?") when so much of the "on the ground" events depend on the character of the person carrying.

[1] Not to brag, but uh, he can shoot the pips out of a playing card while riding by on horseback. He enters contests and such. ;-)

That paper is interesting, to say the least. I don't think that the statistic that you pulled represents everything here.

Things I noticed in the paper:

However, compared with control participants, shooting case participants were significantly more often Hispanic, more frequently working in high-risk occupations1,2, less educated, and had a greater frequency of prior arrest. At the time of shooting, case participants were also significantly more often involved with alcohol and drugs, outdoors, and closer to areas where more Blacks, Hispanics, and unemployed individuals resided. Case participants were also more likely to be located in areas with less income and more illicit drug trafficking (Table 1).

Okay, so it's more likely for people to be shot in poorer neighborhoods, and especially when they're in the vicinity of things that generally involve gangs and other organized crime groups. Carrying a gun, especially an unconcealed one, may be an indicator, intentional or not, of alignment with a party here. Not unsurprising, unfortunately.

In the cases of unprovoked, one-sided violence, or the threat of it, (such as kidnapping, armed robbery [including "pickpocketing"], I think I would probably want to have some ready form of self-defense, be that being physically fit and knowing MMA, carrying around one of those Hello Kitty shank things, carrying a concealed knife, or running some flavor of concealed-carry (please, oh please, do not stick your gun in your purse / backpack).

On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses are possible and do occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should rethink their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures. Suggestions to the contrary, especially for urban residents who may see gun possession as a surefire defense against a dangerous environment, should be discussed and thoughtfully reconsidered.

Okay, so people who think that having a shooty-bang is a sure-fire way to not get shot have another think coming. And? The 4.46 times as likely to get shot statistic feels a little bit off, and I personally think that it needs more unpacking. What percentage of those individuals affiliate with syndicated crime? How many people in the list were involved somewhere in the process of procuring or consuming drugs? These feel like huge stats that are just missing.

Personally, what I would like to research is how many times that guns have reduced the number of casualties in bad situations.

Scene from Total Recall, made 30 years ago:

https://www.youtube.com/watch?v=cWIHv7a6luY

Hexwave:

https://www.youtube.com/watch?v=mOI32PdPew4

"Pre crime".

Right author, wrong short story.

The short stories that inspired both Total Recall and Minority Report can be found in this anthology: https://www.indiebound.org/book/9780806537948

Yes, I'm aware. Wrong story is still relevant.

"Deep Learning"

This looks like totally marketing bullshit. Exactly how are they training their data sets? How does deep learning distinguish a pocket knife from keys?

I call total bullshit. I bet independent tests will show massive false positives (either that or a total failure to detect any real weapons). You're better off with a metal detector.

The "Hexwave" one is bogus - they show a single person walking through the disguised scanners. Anyone that has been to a sporting event can say that crowds at the gates are the norm, and if the system goes off (it false positives, most likely) security now has to identify which of 8-10 people it alerted on. You've just increased the number of people you annoyed by an order of magnitude.

Why was the title changed from "Police To Use TSA-Style Scanners To Spy On People In Public Places"? It was originally submitted with that title, and the title is accurate as Utah's Attorney General has said as much.

Who is responsible for the silent editorializing here? And why?

This is the imaging technology that they are implementing: https://apps.dtic.mil/dtic/tr/fulltext/u2/1033496.pdf

Doesn’t seem to load for me. Do you have a screenshot?

No, sorry, but you could search for Development of a high-throughput microwave imaging system for concealed weapons detection in Sci-Hub.

Try this:

https://github.com/mindcrime/RandomPapers/blob/master/103349...

Microwave? So if we use metal wire mesh clothing it becomes kind of useless. 27 Ghz = 1.1 cm wavelength. That would require a 55 mm mesh. Food for thought for future fashion designers.

You're not going to be able to stop the scanners, but you can probably convince people to employ enough decoys to jam the system. If they're getting false positives on 15% of people, they're going to have a hard time justifying the expenditures.

It's not hard to justify wasteful expenditures already, I don't think this would do it. On the other hand it's not illegal to carry a weapon (per state laws around permits for concealed/open carry) and many people routinely do so, so if this were deployed on a wider scale they'd already detect enough people to make stopping each of them pretty time consuming.

But from the article it's currently going to be used in "mass gatherings like concerts, malls, stadiums, public transit stops and government buildings" which may have individual rules against carrying and so you can treat this as better enforcement (though existing government buildings' metal detectors and x-ray machines for bags seem to be doing just fine).

The more interesting application is combining it with facial recognition. You don't need to approach everyone this system detects, but you can then keep a closer eye on them throughout the duration of the event/their presence in a location.

It's just another step in the ongoing and ultimately futile efforts to eliminate lone wolf attackers while continuing to turn a blind eye towards organized crime. It's not just the scanners people aren't going to be able to stop.

If you want to kill this in Utah all you have to do is say that this will be used against CCW holders.

https://www.sltrib.com/news/education/2018/08/21/university-...

Can’t do the same in California though

Probably a bit too novel but why not just not killing other people? I mean we’ve had a long history that doesn’t include random acts of mass murder why now? Couldn’t we work to fix the actual problem instead of reacting with more theatrics? Seriously, build a culture that engenders good self esteem instead of the abuse laden bully culture we live in now!!!

> build a culture

That's good sentiment and we should definitely work towards it; but do we have examples of our civilization actually doing something like that? Culture continually changes, but to what degree can we influence that change? If we were to take up something like this in an organized way, what kind of precedents or past examples would we look at?

> Probably a bit too novel but why not just not killing other people? I mean we’ve had a long history that doesn’t include random acts of mass murder why now?

I don't know what period of history you're referring to. There has been constant wars or regional conflicts for the majority of recorded human history. If you're specifically talking about home-front terrorism, there is a fairly long history of this occurring too (just the case of terrorism in Ireland takes you back to the late 1960s). Civil wars were incredibly common in Europe in the medieval era, let alone the Crusades.

This isn't to excuse what's happening today (far from it) but to put in context that there isn't a perfect time in history we should regress back to -- rather, we need to move the world into a state it hasn't seen before.

To be fair, it is definitely the case that modern US imperialism (read: waging illegal and offensive wars overseas) is the cause of many modern problems such as the refugee crisis and acts of terrorism. After all, the US is arguably responsible for Islamic extremism thanks to the CIA-backed coup in Iran[1] and countless other countries[2] that fueled anti-Western sentiments culminating in terrorism.

I think stopping rampant (and illegal) imperialism would be far more effective than "building a culture".

[1]: https://en.wikipedia.org/wiki/1953_Iranian_coup_d%27%C3%A9ta... [2]: https://en.wikipedia.org/wiki/United_States_involvement_in_r...

Is this going to be safe for pregnant women and the like? I seem to recall that was one reason to opt out at the airport.

I'd rather be concerned if this is safe for prone for melanoma.

That seems like a weird reason since the radiation counter argument was typically countered by pointing out the radiation from the flight itself likely exceeded the scan by a lot.

This is likely about as safe as wifi. The paper someone linked describes a system using around 24-30 GHz microwaves, one of the company blogs says the power they transmit at those frequencies is even less than a typical router. This isn't unusual. You can see a list of over 800 FCC approved devices in that frequency range here: https://fccid.io/frequency-explorer.php?lower=24000&upper=30... (I also didn't see anything there for Liberty Defense, the company suspects they'll have a product ready by 2020 but we'll see. Radar and imaging applications are tricky, this company could implode beforehand.)

You need to keep in mind the first body scanners were not millimeter wave scanner. They were much more dangerous back scatter x-ray machines.

> That seems like a weird reason since the radiation counter argument was typically countered by pointing out the radiation from the flight itself likely exceeded the scan by a lot.

Doctors often advise pregnant women not to fly at certain stages of their pregnancy.

I can't imagine a doctor would advise pregnant women to enter these security theaters for literally no reason.

> Doctors often advise pregnant women not to fly at certain stages of their pregnancy.

More likely related to turbulences and avoiding entering labor while on a flight and difficulty using the seat belt.

AFAIK, metal detectors (the standing ones) use a simple coil and a receiver on the other side to detect changes in the EM field. The hand-help ones like these ones use either radio waves or microwaves to scan for metal, so non-ionizing radiation. In both cases metal detectors should be safe.

You don't need to have any reason to opt-out from millimeter wave scanners. Just ask for a pat down. I do it all the time when traveling to the US, because I think these machines are useless, expensive and invasive. If enough people did this a simple, legal, act of civil disobedience would force the TSA to rethink the way they operate.

Yes, opt out every time. (With pre-check, I don't have to as often, but every time I'm offered a US-run scanner, I opt out.) Might as well get my money's worth from the security theater... (NB: I'm a quite frequent flier and I've only ever seen one other person opt out; that was leaving a tech conference in Vegas.)

I took part in TSA/Kaggle's competition a year ago.

https://www.kaggle.com/c/passenger-screening-algorithm-chall...

Let me first say that how well these things work is not a property of the scanners alone, but also of the algorithms they run. I'm quite certain that they can be made to work much better than a random choice, unlike what some other posters claim.

The competition did have some issues. For example, the subjects were re-used in multiple scans (although not between training and test2 datasets), and the algorithms were allowed to exploit that (perhaps an oversight in the setup), but most entrants did not actually exploit this fact.

Also the dataset was quite small (~20 subjects). We were still doing much better than random. With a larger dataset and perhaps better scanner design, this would work even better.

Was in russia last year, every subway station/public place had scanners, i just saw thousands of ppl go through them and never ever beep... maybe is just something to scare people?

scanners or metal detectors?

So could Faraday clothing be a new thing then? Outfits that blocks the scanners in public, and gives of a "generic" shape. I wonder how long it would take for it to be outlawed?

Seems likely they'll just treat it as a positive detection until an unpleasant day/evening/night/morning in the interrogation room has failed to confirm that (for this time)?

I've got a shirt that the millimeter scanners don't like. I get patted down every time I wear it on a flight. No metallic lining needed.

How harmful is this to our bodies?

Yeah I wonder if this raises the risk for cancer it can't be good for you.

The scanners in airports are currently millimeter wave machines. They're fucking useless with insanely high false positive rates, but they don't appear to have any health risks (unlike the backscatter x-ray machines from a decade ago, which I'm sure would be facing cancer lawsuits today if they were still in use).

I was under the impression backscatter x-ray was safe (as in this is what every source I've seen says). Any evidence to the contrary?

they were not safe, and they were only approved because the research that said they were safe was done by the manufacturers themselves. They were taken away once academics and other experts showed that the risks were way too high using them

Link?

The person is probably extrapolating from the UCSF study that was done (and debunked thoroughly by various governmental and non-governmental organizations).

https://en.wikipedia.org/wiki/Backscatter_X-ray#Health_effec...

Ironically enough, millimeter wave scanning is less well-understood than backscatter x-ray!

Because companies don't have to prove something is safe, you have to prove something unsafe.

Reminds me of the BPA free garbage. Many of the replacements are/were worse than BPA. But no one seemed to care.

The complaint about BPA was that it's an estrogen mimic (parts of the human body can react to it as if it were estrogen). If you eat a lot (a whole lot) of soy products, soy can do the same.

BPA has mostly been replaced with BPS ... which is also an estrogen mimic.

As a transgender person who has her and her friends frequently flagged for “anomalies” I’m going to call oppression. Don’t look in my pants without asking. Mind your own damned business

This used to happen to me all the time, until really recently where suddenly my junk stopped being flagged. Usually my boobs would get flagged (if they set the scanner to M) or my downstairs (if they set to F.) I don't know why it's not happening anymore... software update? but it's a welcome change.

Would people be even remotely okay with this if mass shootings weren't becoming a daily occurrence? It seems like the 2nd and 4th Amendments may end up mutually exclusive.

Mass shootings contribute fewer than 1% of US gun homicides as far as I know so any policy based around them should raise serious question marks on that basis alone. Otherwise not to be pedantic but that doesn't lead to mutual exclusivity. If there was another amendment saying "the state must take every measure to prevent mass shootings" then you would end up in a "choose two out of three" scenario but as far as I'm aware there isn't one. Satisfying both the 2nd and 4th amendments at the same time is easy to do, you simply accept a certain level of carnage at the intersection of the two. It might be unpalatable for many but it's hardly impossible.

I’d be interested in what percentage of gun homicides they are where the victim had no other contact with guns. That said, it doesn’t matter if the link is zero - anything that the majority of the population feels strongly about can become politically impossible to compromise on, so the relevant factor here is whether mass shootings make people more willing to accept these privacy intrusions.

> It seems like the 2nd and 4th Amendments may end up mutually exclusive

Whole point was neither should be impeded... Living in a society has risks. Overall it looks worse recently, but deaths from mass shooting are still well below just Chicago's murder rate:

https://www.washingtonpost.com/graphics/2018/national/mass-s...

https://www.cnn.com/2018/12/31/us/chicago-murders-drop-2018/...

Personally, I'm not at all afraid of gun violence (perhaps because I've used a gun). Bombs, poisons, etc. and the like are way scarier, as they can kill way more people. Honestly if the occasional mass shooting happens every few weeks, it's a pretty low price to pay (as callous as that sounds).

With scanners and what not there's such a high potential risk of abuse that it's not worth it. If someone randomly elected can decide to imprison million of people they don't like. We probably don't want them to have said technology already in place (and probably want guns).

>Would people be even remotely okay with this if mass shootings weren't becoming a daily occurrence?

...but isn't this addressing a symptom, as it were, and not the problem?

I know I'll probably get down-voted to hell, because this is primarily an American board, but if the issue is systemic to society, shouldn't society redress the cause[s]?

Inb4 the "homogenous" argument: Yes, American society is homogenous but so are other societies. Wouldn't something like, say, affordable (or free), easily accessible and not ostracised mental health tools be equally or even more effective?

I get that people are scared of mass shootings and that drives the reactionary responses we are seeing, such as this, but wouldn't be better to find ways to reprieve the causes?

After all, it wasn't that long ago that "going postal" was a common parlance in American English for such events but those particular events (postal workers "going postal") have diminished - considerably.

Edit: So, clearly, if the rates for postal workers "going postal" have considerably declined, then something can be done to prevent these events - but this would have to be on a societal scale; which is a daunting task, I'm fully aware.

> I know I'll probably get down-voted to hell, because this is primarily an American board

Please don't include this sort of off-topic provocation in your comments. It's against the site guidelines to downvote-bait, and nationalistic assumptions in internet comments never help. As it happens, the HN audience is about 50% in the US.

https://news.ycombinator.com/newsguidelines.html

...which means this is primarily US board.

Define primarily how you like, but it's a lot less that way than most people assume it is.

>> Yes, American society is homogenous

This is... definitely not true compared to the vast majority of the world.

Armed individuals, enabled by the Second Amendment, is largely the reason mass shootings are not a daily occurrence. There's no mutual exclusivity between privacy and a natural right to defend oneself.

> Armed individuals, enabled by the Second Amendment, is largely the reason mass shootings are not a daily occurrence.

No, it's not.

Evidence: the parts of the world with no parallel to the Second Amendment, where mass shootings are far rarer than in the US; in the US, they are nearly a daily occurrence, depending on the precise threshold you set.

The safety, such as it was, provided by the Second Amendment was the disincentive the availability of a militia drawn from the armed populace placed on the reliance on large professional armed police and military forces, which reliance was the threat it was designed as a bulwark against. This completely fell apart a little bit into the 20th Century.

Certainly countries with lower populations and fewer guns experience less shootings, but USA is not such a country and guns are ubiquitous, which is also precisely what guarantees law-abiding citizens the means to thwart assaults and attacks on them.

Conservative estimates of defense gun uses are on the order of hundreds of thousands per year, while unlawful homicides in the mere thousands, and most of these are gang-related. That's solid evidence the Second Amendment is working as intended - to guarantee the natural right to self-preservation for each individual. It has nothing to do with any organized militia now.

> Certainly countries with [...] fewer guns experience less shootings

Yes, which is the opposite of your claim that an armed population prevents mass shootings.

An armed population enables mass shootings, which is why, in total, per capita, and heck, probably even per gun, the US has the most mass shootings outside of actual organized armed conflicts anywhere in the world.

"No guns = no shootings" is an idealized logical conclusion, not a pragmatic consideration for how an existing super-empowering technology can be used by individuals to decentralize and evenly distribute political power, which firearm rights fundamentally are. We are safer and more reliable when the State does not have a monopoly on force.

> "No guns = no shootings" is an idealized logical conclusion, not a pragmatic consideration

Perhaps, but “better control of guns = less shootings” I'd an emninently well-demonstrated pragmatic consideration.

> an existing super-empowering technology can be used by individuals to decentralize and evenly distribute political power

The US has very nearly the least evenly distribution of political power as well as the easiest access to firearms in the developed West, so whatever the US actually has, ideological fantasies aside, isn't a pragmatic solution to that question, either.

> We are safer and more reliable when the State does not have a monopoly on force.

The State is by definition whatever entity or combination thereof possesses a monopoly on the legitimate use of force.

Note the graphic describing a “45mm Pistol.” No such thing.

What does ACP in stand for then? Edit: Oh, you mean the mm part :-) ...actual printed products notwithstanding

https://www.ebay.com/itm/NEW-45MM-PISTOL-GUN-SIDE-BASEBALL-C...

Yes it’s partly cut off on the left but clearly inferrable on closer inspection. The graphic artist doesn’t know firearms. Mostly irrelevant to the article except for peripheral credibility.

For those not familiar with it, the "caliber" system is in theory the diameter of the barrel in inches, so a .45 caliber handgun has a barrel diameter of .45 inches (except in reality it's .451 inches.) Some, like .380 ACP (actually .355 inches e.g. 9mm) are off by even more.

Just noticed that. Hard to take reporting seriously with blatant errors like that. That would be a goddamn cannon.

All the gear and no idea...

I've redacted this post as I don't want to publicise a gaping hole which renders these measures pointless. You wonder if the security serves a real purpose, or is there just to make people feel safe.

Sounds like an opportunity for an underwear company that blocks the scans.

I for one welcome our fact-focused overlords.

The problem is that everyone is guilty of something. The laws are so complex that it's impossible to not be in a violation of something at any given time. Once surveilance becomes ubiquitous, your only choices are 1) put everyone in prison 2) enforce laws selectively. 2) is of course leading to totalitarianism, where no one is ever innocent - I'm from Poland where the secret police during communism operated on this exact principle. No one is innocent - they just haven't been found guilty yet.

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