I'm not saying they can ban you for losing too many games -- after all, Blizz can't blame you for sucking at PvP (due to skill, gear, spec, or any other reason).

However, someone was asking if they could /dance their way to losses in arenas, or AFK their 10 games, and a blue posted that it would be bannable due to nonparticipation. You may lose all your games, but you MUST actually play them. Even if you're prot.