RefRich wroteNo argument with that and I don't believe asking the question is even needed. Ether they are or they aren't and that question will not correct the behavior.
True, if all we're talking about is, say, illegal numbers or something.
But, and this might be more true in other sports (the states / FED aren't going to have the question only for some sports and not for others), if someone is wearing / using something illegal and someone gets hurt by that illegal item, having asked the question can be part of a defense.