tinyE: XD That only works if you register the avatar. XD I may not have a life but I'm not going to do that. :P
Sachys: You don't have to register anything for copyright - it is immediately granted on production of an original work. However, if you have an IP thats worth money, then going through the process with a copyright lawyer can be worth it - particularly in the USA as your copyright laws are all fucked up.
Djaron: because nowadays copyright is the new shit and it overrule even human lives in some not so extreme cases)
Sachys: not really - what you're talking about is corporate lawyers. they cause those kinds of things - not copyright.
as to the avatars - yes - a unique avatar would be worthwhile, though without issuing either a full DMCA complaint or at least being able to fully prove you're the originator / copyright holder, then theres little it would do against scum accounts.
indeed, i simplified it but it is the lawyer thing that brings it on another level, as you said
now for the dcma complain, i heard quite many tales about youtube content being pulled out on behalf of dcma complains of companies who didnt either had any right in the ip concerned nor could prove it at all, yet it worked (sometime the true owner could backward it but only after harm was done.... sometimes owner couldnt because no matter he was the true owner, he couldnt afford financially to backup his legitimate rights against... corporate lawyers)
but yet here in my countries, we had a few "success stories" of CC works and makers (cc for creative commons) who managed to backfire unscrupulous greedy corporations who came to ransack and violate their rights... it is yet too rare, but still, its hope
as for the impersonator and avatar thing, well, i voiced it aloud halfly as a joke, yet on a theorical pov, it is still valid... Thus practically harder to enforce. (and again within a purely national context of mine, meaning for a fellow citizen user on a nationally hosted forum, i assure you it is way easier to enforce for completely non-ip related reasons... but it is then countrywise specific)
anyway, scammers are a plague and very low beings, period.