I was at a game at the Metrodome when I was probably 14 years old. A foul ball came up and bounced off the hands of a 30-something fan several rows in front of me, and caromed right to me. I grabbed it. He came up and demanded that I give him the ball.
I refused, and told him if he really wanted it he could have caught it, and that foul balls are for kids anyway. Now that I’m the 30-something fan, I’m glad I learned the lesson that kids should never have to stand up to adult fans like that.