Add a name to the team member list ???

[Nevadaref]

As you have stated, the proper time to penalize is when the scorebook is changed. If the team member participates and then leaves the game WITHOUT the book being changed to either add him or correct his number in the book, then this change should be made when it is brought to the attention of the official that the team member participated, and a technical foul should be assessed at that time.

I would also do this, if the scorer changed the book without notifying the referee. However, if the officials knew of the change while the team member was in and did nothing at that time, then it becomes too late to penalize the infraction after the ball becomes live.