As long as the umpire(s) judge that the ball can be caught with ordinary effort, it's a Infield Fly. Even if the infielders make no effort, or an outfielder catches, or doesn't catch, the ball.

It's a JUDGEMENT CALL and NOT protestable, or even appealable. Unless, it was not an IFF situation, such as no double-force on the bases.

Bob

As a BU, I've only called IF a few times, and was when I had a rookie (or one time a guy that was drunk).