Forgotten in how the women’s final of the U.S. Open ended is that the problems started with one of the most asinine rules of professional sports. Just stop having tennis chair umpires policing “coaching” from the stands. No gesture made by a coach is going to make a difference, the players still have to execute. Further, the rule is not in any way consistently applied.
Tennis is not “special” because players are on their own, and fans pay good money to watch the players decide that match, not umpires.