In their homes? I'm pretty sure this is illegal. Or is it not if they are visible from a public area?
They know the address being delivered to, and now they can map the presence of specific biometric data to that location and time.
Illegal collection can't reliably be prevented. Get a photograph, extract the biometric data, enter them in your database, delete the photograph. Job done.
Maybe the only way to get control back on this is to require that these databases to be open source (or publicly available) and make it illegal to hide those databases. Citizens must also have the right to be removed from those databases.
I'm not certain how such systems would look in this case (everybody wears Guy Fawkes masks in public?), but this debate reminds me of prohibition vs. harm reduction in the War on [People Using] Drugs.
Just out of curiosity, do you know how that interacts with indecency laws? Like for example if someone is having sex in their home but someone is able to see it from the sidewalk through a crack in the curtains? This is purely hypothetical of course.
My understanding is that it comes down to a "reasonable person" doctrine - i.e. would a reasonable person consider the location to be private.
Another way of thinking about it is if there is a reasonable chance that you will be seen by people engaging in normal everyday activities.
Personally, I would say that peeking through a small gap in the curtains would not qualify as normal behavior. Someone doing that is clearly snooping.
On the other end of the spectrum, having sex in front of a window that fronts a public sidewalk with no curtains would pretty clearly be public indecency.