One guy in our league when receiving always does this. The serve is two feet behind the service line and, instead of letting it go or hitting it into the bottom of the net, he intentionally takes a leisurely practice swing and sends the ball straight back to the server. Two things happen: (1) the server's second service motion is disrupted, or (2) the ball bangs around behind him and he has to wait for it to stop. My solution is to play a let and take another first serve when this happens. Of course, if it's a close serve, you give him the benefit of the doubt for returning it. Anybody have a different take on the subject?