Tony and Daryl,
While it is certainly true that the NFHS clarified that all team members are bench personnel during intermission this year, that is not new. It has been in the Case Book for years.
As for making the coach declare 5 players or have 5 kids check in with the table prior to the start of each period, do you really try to enforce that? If so, you might need to borrow my pipe wrench!