@Derp Counterpoint:
I dont think anyone should be banned from the community or that such a DB should ever exist. People are fallible and bias is everywhere. Having said that there's definitely people out there who have been somewhat "proxy banned" from the community, or are on constant "SpiderWatch" that even if they're now the perfect roleplayer will forever wear that scarlet letter; at least to some players who vow to never forget/forgive.
When you're talking about punishment, public shaming, and how to deal with players, you have to take into account that like it or not some players have vowed never to even attempt to RP on some games if X or Y person has a character bit there, and the casual cyberstalking to try to sleigh-out who is who isn't considered stalking (though it probably should).
When I said that, I wasnt promoting the idea, but simply that there is no "central dbase of worst people ever", and even then it would be highly subjective. The best any game owner could do in my opinion is to dispassionately maintain a whitelist of who is allowed and who has been removed from the whitelist, since public shaming is messy and rife with inaccuracies.