Oh my gosh!! Another wonderful thread.
I especially value DSV's metaphor of being the dance grandparent and sending recalcitrant teenagers home to their parents when they misbehave.
So maybe some good visiting coaches are grandparents or maybe aunts and uncles? It takes a village right?
So BOT what makes a good student? IME (I teach, just not dance) humility enough to allow oneself to be taught and willingness to look foolish enough to try new things.