A user of the famous American NeoGAF forums has posted an image showing how impossible it is to use the party chat while playing games multiplayer of Call of Duty: Modern Warfare 2. The game crashes because this feature, allowing communications only in game chat. The reason? To avoid any impropriety, such as players of opposing teams who exchange private information to assert one of two teams.

Obviously we expect that the whole is confirmed by Infinity Ward, or to be able to see in person once bought the game.