You know what else has already happened too? Tycho has been hacked. That's why he instituted email locks on accounts, because a hacker got into his system and changed peoples addresses. Hacked once...
Please, don't tell about what you don't know.
Most (~14) victims of that attack were using same passwords on deepbit and another pool that got hacked, that's how the attacker got them. Also they were using same passwords for mining and main account.