"Infield Fly Rule"- drop it?

Segment 6 in "trick or treat" month

Runners at 1st and 2nd or Bases Loaded(less than 2 outs) and the ball is popped up in the infield. The umpire will announce "infield fly rule, batter is out if fair." If the batter is already out then why does the infielder ALWAYS catches the ball.

My point is this. I believe at times it might be somewhat deceptive if the infield would intentionally drop the routine fly ball to see how the runners react. Obviously, the more sincere the drops looks by an infielder, the better chance the defense would have for the runner to take off. I would be willing to bet that if the ball dropped some runners might instinctively take off. Now I do think that most runners would not run but some might. The point here is, isn't worth trying this?

If the out is already recorded why do you need to catch the ball and record the out again? Why not let the ball drop and see if you can get one of the runners to take off and see if you can get a second out? It seems similar to the offsides penalty in football. You're guaranteed 5 yards, why not take a shot downtown.

I never see this happen but I think it has merit and should be seriously considered when the pop up is routine.