Well, if the guy knows where you live and shit, he may go on a rampage or something who knows... :P
I usually don't recall accounts I've gotten money for, I usually only recall traded ones and shit. Since you're OO if you really want to, you can have them change the SQA and crap so he CAN'T get it back at all but for that you'd need to mail in your ID and crap.... All in all it's up to you imo.