The rule is actually a good rule when it's used correctly as it is 99.99% of the time. The runners on base are in a "no man's land" on an infield pop up. If the runners try to advance the infielder will catch the ball and double up the runner. If the runners don't try to advance then the fielder drops the ball and the runners are screwed because they are still sitting on base. It makes for an easy double play. The problem with the call last night was it wasn't an infield fly ball even if the shortstop was callling for it, and even if it was the umpire should have called it immediately and not a split second before the ball fell between the two fielders.