[just another ref]

I'll try one more time. The officials did not realize the team had 6 on the floor when the basket was made, or they would have made the call before the basket was made. When a team has 6 players on the court, it is not always because too many came out after the timeout. A1 looks up from the bench and mistakenly counts 4 players. He realizes (incorrectly) that he should be in the game. He jumps up and runs onto the floor. Officials should make a habit of counting the number of players after the timeout, but, like anything else, this can be overlooked or a mistake can be made. When the official does see 6 on the floor, he will have no way of knowing when the extra player appeared.