I don't steal signs. My daughter looks for change up signs right away and works with the other girls. She usually has a phrase like "it's all you Smith" that tips the batter. It is something she does on her own and I am fine with it. We have played a lot of teams that the base runners tip pitch location. Myself, at 12u, think that could be as harmful as it is helpful.
My first year 12U DD was pitching in a tournament last summer and I was giving signals from behind the fence. I was calling change-up, fastball and 'throw it as hard as you can'. I had already told my DD several times she doesn't need me to call the pitches, she knows what pitches she should be throwing and when, it was more of a comfort thing for her. I told her I would help her this summer but after that she is cut off, she needs to work it out with the catcher.
The opposing team noticed I was giving signals and the head coach sent their assistant over to see if they could figure out the signs. It turns out the assistant was a good friend that I played basketball with so we started talking and he told me why he was coming over (to steal the signs). I told him what the signs were and told him it didn't matter if they knew what was coming or not, at that age (and their skill level, they were an average B team) it was of little value. I told him I could yell out the pitches if he would like, it made little difference.
Sure enough when it came time for the change-up the HC would yell, "Watch out for the change-up!". The girls hadn't practiced hitting fastball then change-up so there was little that they could do. We won the game 8 -2.
when my dd was 11 her and the other girl who was catching for their team, would steal the other team's steal sign from the coaches all the time. Not such a big fan of coaches doing it, but if the girls are savvy enough I'm fine with that.
If you can figure out what the other coach is trying to do with his batter and runners, I will use it in a heart beat to help my girls defend it.
Sometimes it is pretty easy to figure out the pitching signs that the coach is giving from his bucket or from the fingers the catcher has dangling about 5 inches below her. It is to much troulble to relay what the pitch is to the batter for me.
But if I know what the offensive team is going to do, I will call a number to the infield of what I think is going to happen, that coresponds with our own wrist bands. so if I think someone is going to push bunt the ball , I will get my 2b attention and give her 2 numbers and she will know what might be going down.