6 on the Court -- unnoticed...

[Nevadaref]

Originally Posted by Freddy

"If the entry is not legal, the substitute becomes a player when the ball becomes live." I get that.
If, however, that entry were a sixth player and it was discovered after the next whistle?

Then it is too late to penalize the infraction, even though you know that it happened.
Keep this simple. A team member participates by becoming a player. The definition of a player is in the book along with how a team member becomes a player as well as ceases to be a player.
The six team members participating is a little cloudy because the extra member isn't a legal player, but is out on the floor when only players are permitted. That's actually the infraction and why we can't penalize when the ball isn't live such as during a lengthy susbstitution process with multiple members entering and exiting. We need a time when only players are allowed in order to penalize a non-player being on the court.
Certainly, there need to be clear demarcation points at which play starts and ends as well as for when it is too late to penalize things which happen yet were missed by the officials during the game. For participation, the NFHS has selected when the ball becomes live and dead as those points. Similar to correctable errors.
What you seem concerned about is the timing and want to penalize when the team members are still on the floor during the immediately ensuing dead ball period. It seems unfair to you as this point in time is so close to when the infraction occurred. So take it to the extreme. What about missing this during the final seconds of the second quarter and having it brought to your attention just prior to the jumpball for the first extra period? You obviously can't go back and you feel comfortable about that. Why? You know inherently there is a point at which it becomes too late, but you are just fuzzy as to when exactly that is.
For the NFHS, it is when the ball ceases being live. Now you know and need to make the mental shift to accept it.
That can be tough, but as I mentioned above, this is no different from the timeline for correctable errors. Once you pass the point of no return, it's over and you're done with it. It doesn't matter how soon after the deadline you catch the error or how egregious it was. Now apply the same mentality to six on the floor.