The coach makes the decision to play them
This statement is true, and by sitting kids who lack discipline it can be instilled in them - at least while they are competing for a coach that demands it. I've witnessed it first-hand happen numerous times.
Almost all kids want to play more than anything else. They will conform to the guidelines if they know they aren't playing otherwise.
I think that it was Buzz Williams who said that the bench was his best teacher. I agree with that completely.
I think that we are also seeing this, in some degree, with CJP.