Yeah, that's what I meant (and couldn't properly articulate).

So the difference is the reporting mechanism, that allows a powerful organisation to make meaningful threats to protect others?

Because in [Garfinkel 2003] it's similar: returning users get a big, fat warning, but they can't meaningfully do anything about it on their own, except not trust the other side.

(http://simson.net/clips/academic/2003.DGO.GarfinkelCrypto.pd...)