[TSAdmin]

I've seen this, as well, but not just for the same account, either.

EG: I log on as TSAdmin (I barely ever change my name from *TSAdmin), then close off Graal, and say my brother wants to have a go at Graal for a change (Since he never plays) so he opens Graal and clicks "Guest" and changes the name in there to his desired name, logs on, and gets inundated with "OMG, ADMIN IMPERSONATOR! JAIL HIM!!! YOU'RE NOT TSADMIN" and he doesn't even know what they're on about.

*That is all while logged onto the local computer as me, no user changing took place*