I present this thread as a prime example.
While it's possible the TC really is insane as several people have suggested, the fact that so many people decided to give him their attention is pretty sad when you see their posts.
I also remember one instance I saw a few months back where a new user tried to stir up trouble on General WoW and was swiftly permabanned. Before they were banned (I think it was Sunshine or Chaud who put them in their place, can't remember now) they mentioned something to the effect they have other accounts and will simply make more for each one banned.
Outside RPing and/or Mods who want some privacy, there's no real need for anyone to have more than one account. Methinks a general reminder to everyone weather they have multiple accounts or not should posted to let everyone know if one account does something banworthy ALL of their accounts will be banned regardless of how long they've had it.