I just got an e-mail notification of a game being deleted, which is not terribly unusual. The thing is, I never knew the game existed to begin with!
I did play this person before, and the game ended 11 or 12 days ago -- I looked.
My game preferences are set so that when I make a move, I go to the next waiting game if there is one, so I can't imagine he had time to offer a game and then delete it. Someone else (a month or so ago) got a rematch game from me that I never sent, so I wondered if that was what happened here. Mysteries drive me nuts, though.