So you foul and give more free throws? Or just contest a play to stop a fast break? It would give defense a time out effectively. I see so many problems with this idea. It will never happen. Ref mistakes are a part of the game.
I would rather have a fourth ref watching from the angle of cameras.
Well you foul 'only' if you're confident about your challenge. If the challenge is successful then obviously the foul you've just committed is nullified because it would have been a dead ball situation if the ref had gotten the call right in the first place.
So you've got nothing to lose if your challenge is successful.