My daughter's ballet class is also a closed class, I guess I could try this too so that I'll find out how her teachers behave when no parents are around.
Your son is a great student and an even greater teacher. And this technique you just did is also like a way for him to directly and indirectly narrate back everything he heard and learned from his arts class.
I hate closed classes.... If I don't know a teacher well outside them, how can I trust an unfamiliar person? First impressions can be so wrong. So yeah, this "game" can really open much truth;) And of course mother's heart will always feel and see if anything is wrong with her kid.
Baller class - wow! how long do you attend it? it's as so complicated art!