Sub for foul shooter

[Jim Henry]

It’s overtime in an 8th grade girl’s game. Team A shooter is fouled with 2 seconds left; with Team A down by 5 points. I call the foul on Team B and award 2 shots to shooter. Team A calls timeout. Team A coach comes to me and says his shooter is hurt and that she has to be substituted. I ask about the injury and she is holding her knee. I allow the substitution and allow the sub to enter the game and take the two shots. Was I duped? Was the sub their best foul shooter? Or was it a legitimate request from the coach? What can I do differently to avoid being tricked? By the way, the fouled shooter made one of two and their team lost.

Thanks.