You are right RB. There would be trade mark issues. This why Sean O'Connor called his game Conquest. Maybe the MapPoint war game could be called MS Domination of Redmond Wars or something that plays on MS's global market share.
Years ago I flogged MI and we had a game in MapBasic called RISK. It was used to teach new users how to use MapInfo. No one seemed to mind. I see a guy named Steve has a simliar thing over at the Directions Mag Blog.
http://www.directionsmag.com/files/index.php/view/613
The great thing about doing this in mapping software like MapPoint is that you can change the starting territory setup and thus change the game/strategy for different territory layouts.
Ciao,