I am a mother of 6 children... Ages range 32, 30, 21, 20,15 and 9 yrs of age. Over the years the kids have been involved in varies school and after school activities. I have NEVER encountered this type of issue!
Any of the activities the kids been involved in has always been in the theme of everyone gets to play. Except for HS football. When my son was in HS football, the earlier years (freshman,sophomore)he didn't play as much as we have wanted him to do so (he was quarterback)However, by the time he was a senior he was the starting quarterback. I believe Bobby's informative times were the years before at practices and scrimmage games. Other than the HS football, all my other kid's activities were as I stated above, everyone got a turn. For some parents, I noticed they weren't too happy w/a plan like that.. As with some games there were teams leading nearing the end of the game, until they put in kids who didn't play as well as the players before and ended up loosing the game. Though at sign up, it has been stated in the contract "everyone gets to play", and we paid our money and signed on the dotted line.. Still some parents were offended about that type plan of play..

Had I expirenced what your are, no doubt, I would talk to the coach as you did. Like yours, my children rather I not do so (like with other issues of nearly the same nature) I still go ahead and speak up about the issue's I have, and would keep doing so until the matter was addressed on a ongoing basis. I also would tell the people who are in control that my child rather I not say anything, however I know my child is having a problem with this and doesn't want to be the child that has their mother going up and making a big deal about it or the coach being offended and perhaps be making to do something that isn't in "his" plan, and then maybe perhaps taking it out on the child.. In reality the child is secretly wishing something would happen. I promise you, if you speak up enough, this will be a non-issue after some time.. And if someone in control is offended about your claims... Too bad! It's all about the sportsmanship and the fun of the play! It's not about the adults, parents or coaches!