[JackC]

Oh, another example that affects even the one-way lookup is stalking -- if I've been over to Joe's house before, and then he goes into hiding, I can say, "hey, I see Joe's access point, where am I?"

That could be mitigated by requiring at least two access points for a query.

[hannosch]

Both the Mozilla API as well as Google have this "you need to know two" protection. At Mozilla we go a bit further and also make sure the two BSSID's you are sending aren't almost identical. That happens in a lot of modern access points who are setup with separate 2.4 and 5GHz networks or those who have a guest network.