I understand completly what you are going through. At the begining of every year I have a team meeting with the parents. At this meeting I go over all of my expectations of the players and the parents. At the end of the meeting I give the parents a letter basicly going over what I just told them. This letter is to be signed by the parent and the player and returned back to me. So far after doing this I have had very little problems with the parents because they now know what is expected of there child and themselves and what will happen if they do become a problem for the team. Good Luck