Idea: Location-based region assignment

[burke]

I'm on the fence on whether this is a good idea, leaning towards no, but:

• We could use GeoIP to get approximate lat/lng of the client;
• We could convert this to some fixed-length prefix of an S2 Cell ID;
• Using that as the region, the client could fetch regions in a radius around them.

I think this is a really brilliant strategy (cribbed completely from one or two other implementors), but:

Even though this actually gives away no additional information (IP address is inherently public on the wire), the perception of a contact tracing app "knowing your location" could be an extra hurdle to gaining widespread adoption in the current North American political climate.