I had it happen early in my career. It was at a 7th and 8th grade game. The coach put the kids up to it and we caught it after a timeout. We just got the right kid at the line and went on like nothing happen.

Some other signs. You call a foul on the floor against a post player, and the hot shot point guard who was nowhere near the play goes to the line. You call a shooting foul and the wrong player goes to the line, and the right player isn't trying to fix it. Especially if there isn't a timeout between to add confusion.

I can say that I have not seen a player of mine get confused except when there is an off ball foul and the player on the ball also got contact and thought the call was on her defender. It is usually pretty clear, and if the players make a switch that looks highly improbably, it is highly improbable that it was mere chance or confusion.

And you use the word prove. You don't prove anything. You make your best call and stay with it. It's not that kind of court, and the standard is different ;)