This is something else, besides pitch count, that I have to talk to my son's HS coach about. My son is the best catcher on the team as well as one of the top 2 pitchers on the team.
The coach is known to take a pitcher and move him to another position in the same game. Usually my son plays 1B so it hasn't been an issue.
As I stated before there needs to be clear enforcable rules to help prevent injuries to pitchers so that parents don't have to worry about it.