Is game chat on gabbly acceptable?

Just a quick question: Is it fair to be talking about your next move, and making plans with other players on Gabbly whilst playing a game? I haven't bothered to check to see if these guys have announced an alliance in the games or not, but I often wonder if thats whats happened to me when suddenly two or three players turn on me in a game. Im not whining, just curious if this is accepted strategy. It leaves a bad taste in my mouth! grrrrrr.... 
