On January 10th(2012) there was a team technical foul assessed to a JV team as a penalty for a varsity player, warming up with the JV team, and dunking. The game started with 2 free throws and the coach lost the use of the coaching box for the night.
As a history note, when the rule changed to return dunking to the high school game there was a question as to why dunking would be allowed during the game but not in warm up. The answer given at that time was that during the game, only people that know they can dunk will attempt to, but during warm up, players who can’t dunk would try therefore risking injury and possible equipment damage.
Below is the response I received from Dennis Morris regarding varsity players dunking during JV warm up periods in Ohio.
If the coach allows the varsity team or any players to warm up/shoot around before the game they DO fall under all rules, so Technical foul. If they shoot around at half time AND the JV officials are out there I believe that they DO have to follow all rules etc.