It is not a stupid rule. On court coaching is allowed for Womens Tennis Assoc only, in tournaments except for Grand Slam events. A player who is talented enough to be competing in a Grand Slam should have the skill and ability to problem solve on their own.
It IS a stupid rule......Why shouldn't ANY athlete in ANY event be denied coaching during whatever event they are competing in?
What advantage would a tennis player get from their coach on the sidelines that their opponent wouldn't also get from theirs?
Tennis is the only sport where chiropractors pass out their business cards outside the stadium to take care of spectators wandering out with neck injuries..........