Actually, consistancy failure is just when something isn't consistant between the server and the client. A common cause of consistancy failures is anytime something gets desynchonized between the host and the joiner. A particularly nasty one from earlier versions of SRB2 would cause a player joining a CTF netgame to spawn at a deathmatch start on one side and a capture the flag start on the other, so when the player moved, the game would check what sector they were in, find a contradiction, and kick the player with a consistancy failure.