@jl2012: Yes these are correct questions.
1- In the non-virtual world, I believe that person would lose anything gained from a thief (in case of a suit of course), that could apply to a virtual currency. You could add delay between being able to send newly received funds, but that seems like a major hassle for the overall population so maybe not a good idea.
2- Well that's part of the risk of course, would the cons be greater than the pros? maybe.
3- If it is done at the user level, I doubt people want to manually keep up with small stuff it'd be a hassle.
Probably the same if some organizations are in charge of "blacked lists".
I suspect it would be mostly focusing on the BIG ones, like Sheep, Gox, etc. In these cases it probably makes no difference if the claim is legit or not (ie if an external thieft came in, or it was an internal job, both end up with the same result)
But you didn't reply to my question about the fiat, why?
In no part I assumed I knew exactly how something like this would work, I am merely asking the question.
(most of us didn't know how to get a P2P currency and yet we have one now...)