Every person I know who plays WoW in my inner circle got their account hacked, including myself. It's a pain in the ass and fucks up not only your shit but your Guild's shit. Guild's have communal banks in which they share rare materials and items, and when someone with tons of access to it (like, say, an officer to the guild) gets his account hacked that asshole also plunders the Guild Bank, fucking over the rest of the guild.
It's too common.