We have learned to respect the unbelievable knowledge and experience of parents who have watched many games and almost to a tee played none. Without parents, there would be no girls to play. With them, it sometimes becomes a challenge.
We have instructed our players and parents, and they know beforehand, that if they heckle or become overbearing in destructive or demeaning manner, that their player will be sent in uniform to sit with them in the stands. On only one occasion have I had to speak to an uncle who immediately quieted down.
In our game this week, with our head coach in the hospital with his daughter, several parents who did not know the strategy or tactics he had put in place, screamed at their daughters and demanded that they play in positions that they had been instructed not to play in. That confusion may have lost the first game of the year for the team.
Some parents are perfect, and have enough inner confidence to allow coaches and teachers to instruct their children. 90% of the parents I have come into contact are this way. However, there is, every year, a parent or a couple who cannot give up the "power" and control of their child and must be the loudest, most demanding, etc. even from 50 yards away and to refs and administrators. One on one is the only way to handle this. In front of others never works. Explain to them the rules, and make them follow them.
100% of our parents complained, screamed, and yelled about a call or two that were obviously ridiculous. Can't, and wouldn't want to, stop that. It is the only way to keep a kid from getting kicked in the face.