Someone messed with him the first time for sure, that is why he switched from being Duke Togo to Godzilla. I think someone figured out his password, the second time he thought he was hacked was a changing of a poll's status from being a poll only to a poll that allowed for comments... I don't know about that incident, a great deal happened that afternoon and resulted in him leaving MW.
Lets face it though, everything is hackable. I am sure that the team that wrote the software for Invision can hack any account in nothing flat... The hack for any board is out there, it is just a matter of getting someone to tell you.