Manual contact tracing support via App / Privacy friendly exposure tracing

[ozppupbg]

Hello,

with many places reopening and applying measures to support contact-tracing efforts by people leaving their contact data and not necessary beeing hygienic (everyone touching the same paper/pen) and by no means privacy friendly, I got an idea.

The "existing" Exposure Notification infrastructrure could be used to help in these efforts:
If some sort of "location" beacons would be installed in the shops, restaurants, etc. and broadcast EphIDs/RPIs these could be picked up as usual by the app.
In case a manual contact tracing or (in case the location beacons also record EphIDs/RPIs) an infected "contact" is detected, all possibly affected/exposed users of the app can be informed via the usual channels (uploading the keys to the central repository).
Another option would be to use static 2D-codes with fixed IDs, which can be scanned, e.g. when entering a place.
These methods could improve the exposure tracing in places like toilets or restaurant tables, were you are likely to touch the same (possible infectious) surfaces as the person before you - even, if you were never in close contact with them.

Some things would need to be worked out - e.g. identifiying such location beacons via the encrypted metadata, processes to allow uploading keys based on exposed location beacons or how to determine exposure time for the 2D-code variant - but I think it would open a lot more use-cases.

As an additional benefit these features would give more incentive to use the contact tracing app.