'T' not warranted???

[Texas Aggie]

what do you do when, during pregame warmups for the JV game, one of the players dunks? ... he's not in the book

Being in the book has nothing to do with anything. The Rule 10 technical reads "player." Since a "player" is one of only 5 at a given time, the rule's intent is actually "team member," which includes everyone in uniform who is eligible to be a player. The rule in Rule 10 probably should read "Player or team member" to cover times when more than 5 can be on the court -- such as pregame and warm ups. The book isn't required to be complete prior to 10 minutes before the game (and, individuals can be added later as well at the expense of a penalty), yet the officials' jurisdiction begins 15 minutes prior. You're still going to call a T for an apparent team member who dunks at 14 minutes prior even though he isn't yet in the book.

Don't make this hard: if he is a team member, T. If not, tell game management to tell them to stay off the rim. Its not your job to involve yourself with non team members.