Comment by aclelland | Hacker News Reader

Comment by aclelland | Hacker News Reader

As someone from the UK, I'm really appreciative of all of the people who are actively looking into the app and highlighting privacy, security and other concerns.

My main concern with all of the contact tracing apps is that I live near a very busy road, hundreds of people per day walk past my house and they're going to be about 3 meters away from my phone, albeit through a brick wall and a 6' hedge. My concern is that the apps will pick up the random passers by and I'll be forced to isolate my family based on a false detection.

Maybe this isn't an issue and these apps will have protection against this sort of false positive. I've yet to hear either way.

edit: Thanks for all the answers! Definitely helped calm the concerns about this sort of false-positive.

> I'll be forced to isolate my family based on a false detection.

Installation of the app is voluntary, and there's no sign that's going to change. Forced installation would probably be politically and logistically impossible.

If this was a problem, workarounds include deciding that the app wasn't usable in your situation, or turning off bluetooth on your phone while at home.

As far as I understood the apps are designed to measure time of being near someone as well.

I think within X meters for Y minutes (based on how often the bluetooth pings are exchanged).

This also has basis in virology where rate of infection for flu/corona substantially increases when you are close to someone within X meters (say 1.5m) for longer than a defined time Y (say 10min).

The current app needs two phones to be in contact for at least 15 minutes before it triggers anything.

Firstly, people briefly walking past your wall shouldn't trigger either system as they're both set up to require a period of time and a certain signal strength.

Secondly, situations like this are possibly one of the situations that will benefit this NHS-style centralised contact tracing over the distributed one as they can apply more advanced models to the nature of the exposure and try to reduce false positives. Or indeed, potentially expose that information to human contact tracers (though right now they say they have no plans to do this).

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