There are good reasons not to do this. The main reason is you risk the ball handler anticipating the foul and taking a shot, perhaps resulting in a three point play. It might be unlikely, but it is possible. If you play good defense, you have a better chance at a good outcome. The Washington play never should have happened, the fault was not with Brad or the scheme, but Morris foolishly came over to contest the lay up leaving Meeks open at the 3 point line. Morris admitted after the game that he goofed. If Morris stays home Washinton scores 2 and the game is likely over. It is telling that most NBA coaches, even the best ones, do not do this.