The policy is that we don't allow multiple usernames for a single person because it's deceptive. Like you said, for the most part everybody adheres to this. But there are definitely a few psychopaths that go to great lengths (like using proxy servers to randomize their IP addresses) to create multiple usernames because they are pissed they got banned previously.
Thank you for the note, Baron. Would you and Magna like to be informed of users that are definitely reincarnations of themselves or would you just prefer it to work itself out? I can certainly understand if you choose the latter, as you may open yourself up to all sorts of "crying wolf" on the subject. But there are a few out there that are clearly another version of their old self.
We'd like to be informed of reincarnated users for sure, but the best way to do that is by starting a private thread with Magna and then posting to that single thread whenever you have someone to report.