So.. What I think is going on - mtgox lost quite a bit of coins due their error and now try to recouple these with stealing money from smallish and new accounts!
Be careful before you state your single opinion (keyword=think) as an "official" statement. I'd revise your subject.
I know they are stole these. "think" is related to only small part where I am trying to come up with meaningful explanation why.
If you do not like this explanation, how about this one - they simply could do this just to steal fortune and purposefully exposed their DB to "explain" why their users lost their coins.