I don't think we will have to worry about it. The few high school coaches I've talked to so far are not receptive to releasing their kids to miss the first week of practice.
Fortunately it is not the coaches decision.
If I choose to allow my child (student athlete) to participate in a pre-season tournament prior to attending any high school practice session - the coach is junk out of luck.
The coach will not dictate anything to me, or my child, prior to my student athletes participation in the school program.