The purpose of a stunt is to confuse opposing blockers, which is an aid to the defense in rushing an opposing forward pass or kick. The main weakness of a stunt is that it is more vulnerable than average to running plays by the opposing team. In most cases, the defense will not use a play incorporating stunting if it expects a running play from the offense. Because of the exchange of roles, a stunt is sometimes called a "trade"; blockers of the offensive team may engage in similar "trades". The defensive players involved are said to be stunting or trading, or sometimes to "have a game on".