I noticed today that someone's called their user account 'Server Fault', personally I believe it implies, whether intended or not, some form of ownership/authority/legitamacy.
I'm sure it wouldn't be too hard to implement at account creation time, in fact there could be some form of blacklist of words/phrases we don't allow - I'm all for freedom but don't really want to be answering questions by users with obviously offensive user names.
By the way there are LOADS of users on SO called 'Stack Overflow' - I really don't think it's a good thing.