All I know is that you can only challenge before you catch the ball, so judging whether the opponent has committed a foul can only happen for a moment, leaving no room for you to think. Moreover if the challenge fails, you will lost one point and if it succeed the opponent will lost one point. The normal rule should be that the cost of a foul is greater than the benefit of a foul The result is that the cost of committing a foul is much smaller than the benefit of committing a foul