for travel ball, i see no problems with your position. BUT high school is an entirely different world.
It is, but if they're even more dependent on one pitcher than travel, they should be even more mindful of what the girl and parent want. At least at our school, travel ball is higher level and more important than school ball.
Now it's rare that the load is ever too bad, but there is an upper limit. I doubt I'll ever have to step in - just saying I will if need be. Better yet, my DD will.