sub or not??

[BoomerSooner]

Just as a hypothetical spin on this, but what about after a time out when A6 has properly reported and the coach forgets he had A6 set to go into the game. Warning horn sounds, no other players can sub into the game at this point and A5 who A6 was set to replace goes to sit down on the bench, however the other 5 players (A6 included) are on the floor. With play almost ready to resume (team B breaking the huddle), the coach realizes who is on the floor and tells A6 he isn't supposed to be in the game. Then do you force him to stay?

The importance of this scenario is that there are times once a player is beckoned into the game that he should stay, but I do think depending on the situation if another player reports in a timely manner A6 from the original situation doesn't have to stay.