If the opponent acknowledges that he is uncertain, he loses the point. There shall be no further delay or discussion. Spectators never to make calls . A player shall not enlist the aid of a spectator in making a call. No spectator has a part in the match.
Prompt calls eliminate two chance option .
A player shall make all calls promptly after the ball has hit the court. A call shall be made either before the player's return shot has gone out of play or before the opponent has had the opportunity to play the return shot. To illustrate, a player is advancing the net for an easy put away when he sees a ball from an adjoining court rolling toward him. He continues his advance and hits the shot, only to have his supposed easy put away fly over the baseline. The player then claims a let.