Ditto - several years ago I was watching DD's 12U game. Our team's pitcher for the game was doing great - typical 12U fastball/change-up and the batters couldn't touch it. Next inning, the opposing team's batters started hitting the ball hard. All of us in the peanut gallery were perplexed until we figured out that our catcher wasn't doing a good job of hiding her signs - the opposing coach was stealing them and signaling to his batters "fastball" by saying the batter's first name, or "change-up" by saying the batter's last name. Our coach called time and had the catcher change her signs and hide them more effectively. It was an interesting study in a batter's timing when she knows what's coming 
