Just played a 16 hour game of Axis & Allies (classic). I thought the guy playing Russia just didn't know what he was doing, but it turns out he had made a deal with Japan to just leave him alone. Thus it basically became Russia kept to himself while the UK battled Germany and the USA fought Japan. Needless to say the Allies lost handily.
Is this allowed? Can a player basically switch teams or have a truce with the other team? Without any other players knowing?