Limiting the devices to two per person seems nonsensical to me. The devices are either dangerous, or they're not. If they're dangerous, two is too many. And if they're not, then why limit them only to two?
That's not actually how it works though, it's all a risk and percentages. Nobody says "driving is either safe or it's not" or "delivering a baby is either safe or it's not"
To make it clearer, imagine another context: "It's dangerous for a passenger to have a gun on board. Therefore, we're strictly limiting passengers to only two guns."
Like, no. The relevant sad case is present with one gun just as with two.
Of course, what complicates it is that these power banks present a small but relevant risk of burning and killing everyone on board. So yeah, you might be below the risk threshold if everyone brought two, but not three. So it's not inherently a stupid idea, but requires a really precise risk calculation to justify that figure.
A mitigation is anything that reduces the probability or the severity of a risk. There are different categories of mitigation, some of which are more robust than others. Once the risk score moves below the acceptable threshold, the risk is satisfactorily mitigated.
Example: Rapid depressurization. Without mitigation, the risk of rapid depressurization is unacceptably high. So we mitigate the probability by requiring sensitive inspections for metal fatigue, and we mitigate the severity by providing oxygen masks, a standard flight crew procedure for making an emergency descent, and regular training on that procedure. (Plus a bunch of other things I'm not thinking of off the top of my head.)
Assuming ICAO did their due diligence - and I don't have any reason to think they didn't - they would've assessed the probability and severity of all of the ways a consumer power bank might fail. That analysis is the rationale for both the number of power banks allowed on a flight and what you're allowed to do with them. And yes, they will have considered the probability of people not following the rules (which is the reason, btw, that airplane lavatories have enormous "no smoking" signs right above an ash tray).
I’m not sure what you mean; when I Ctrl+F “shampoo”, this is the only hit I see.
Someone bringing 150 "lipstick" single-cell promotional chargers -> bad
Someone bringing one phone and one laptop battery pack -> OK
If you are limited to two, you are probably not bringing anything that is near e-waste quality.
Two powerbanks contain the same amount of energy as a hand grenade.
Maybe there is enough plane onboard capacity to deal with just 50 batteries, let's say; multiply the failure rate expected and the pax capacity of the plane and you get how many batteries you can afford to have onboard and still be able to deal with worst case scenario.
What you're saying is equivalent to claiming that this quantity is somehow independent of n.
Clearly, battery packs have more legit utility for more people at much lower risk than a bomb.
It's not fallacious, it focuses the issue, and in this particular case shows that it's not about "binary thinking" it's about risk.
And my original puzzlement continues. At what level of risk, does limiting the number of devices on board to 500 or even more, actually accomplish anything?
If they're not all that dangerous, then why limit them at all? And if they're dangerous enough to limit at all, why in God's blue sky, would you allow that many of them on a plane?
We don't limit people to 1 knife per person, even though knives have utility to a lot of people who carry one with them every day.
Because it's a numbers game... the original order itself even acknowledges that the problem is not unique to power banks, but that what makes power banks unique is the amount of increased risk they pose compared to other devices, due to a higher ubiquity of them in general, and of low-quality unsafe ones.
If laptops were catching fire with the same frequency, they'd ban those too, but they're not. They technically can be made just as unsafe as power banks, but they usually aren't, and this directive is based on the frequency of occurrence of a particular type of device, not a general "what if" strategy.
Banning all electronic devices would be extremely unpopular and possibly tank their sales. They're trying to balance safety with convenience at a level that is acceptable to most people.
* Less likely to be of the same low quality
* Less likely to all go off
* Less likely that someone is doing something malicious/suspicious with it
vs. someone who has 20 power banks themselves in a bag, in which case if one of them catches fire unexpectedly, they will probably all go up at once and create a cumulative effect much more dangerous than 20 individuals.