I recall a few years back I saw a friend running around on WoW. When I talked to him in game he didn't say anything so I messaged him on MSN "OH hey I didn't know you started playing again" "I haven't" long story short he appealed to Blizz and got everything sorted out.
The way my strange mind works however I can't help but feel sympathy for the guy who goes online and buys an account only to have it closed off because it's a hacked account and because I saw it, he's now probably out whatever money he payed. I can only imagine how worried that guy got when I messaged him trying to say hi if that was the case.