I've always liked this idea! I think it should be device-level too, and not have a separate ephemeral identity. In other words if you get a new phone you have to start over.
So does the person who finds the phone inherits the identity? Can we have influencers selling off their circles? When I get robbed is my mugger now friends with my grandma?
No, it's adding friction for honesty's sake. You don't have six thousand friends. You have five friends, tops, and like two hundred acquaintances tops[0].
There's nothing to "get back into"-- it was all just a lie to flatter you. The network effect stops working for you in the low three digits. You're just part of a people directory owned by some corporation.
For Facebook I keep my friends list light - less than 50 people, but there are people who I live a far ways away from - my parents for instance are 5 hours away. I don't want to have to drive to them just to prove they should be part of my social network.
