There is a warning/ban system and that would likely qualify. If you go back to the game in question, you can click on his name in the bottom right to bring up a small window. In that window, there is a 'report' button. Click away
Impolite player "TheGreenerGreen": 12/5/2011 16:02:34
Also, for future reference, you can post a direct link to the game, chat and all, by going to game settings and grabbing the URL it provides. This is true only for multiplayer games but allows for other users to view the matter first-hand and get the full story.
Impolite player "TheGreenerGreen": 12/5/2011 22:41:33