Sparky, sorry but I would change the first sentence to The hardest thing is to teach parents (or could be grandparents, aunts, uncles)....the difference. I don't think kids need to be taught the difference. They have teachers at school who are coaching them in class (I don't mean sports) but not parenting them, if that is what you mean.
A lot of kids don't like hearing it from their parents. The same critique they would listen to from another coach is dismissed when it comes from Dad. A girl on my team is a dream to coach, she is focused and intent on everything I say. She immediately tries to implement what she just heard. Her father is her basketball coach, no matter what he says she feels personally attacked and tends to shut him out. On the other hand my DD would rather not hear from me at practice, but she will listen intently to other coaches. She loves her basketball coach (other girls dad) and will listen to everything he says.