Generally I have always had very involved parents. My mother was very involved when I first began riding and it has been a huge help. I like to make sure they are comfortable around horses and understand what their children are doing.
However, when it comes to them trying to teach I am very upfront from day one. I explain where the parents are welcome to watch from, and if they have questions or concerns to only bring them up during breaks or after the lesson. I focus very much on the student, especially early on, keeping a dialog and their attention.
Maura I think I have said exactly what you say (I'm also pretty sure it was said to me very early on). And if I need to say it, I make sure the parent has heard me. I have only come to blows once with a overly pushy parent. She was bent on her child jumping when the child was barely comfortable cantering. I stood my ground and explained why a student needed the foundation her daughter was receiving and she would advance when I decided she was ready. They took her elsewhere, and that was just fine with me.... felt bad for the kid, she eventually got hurt.
If your horse says no, you either asked the wrong question or asked the question wrong
And God took a handful of southerly wind, blew His breath over it and created the horse