Warm up dunks

[bseybs32]

JV boys game. Actual situation.

Players are dunking in warm ups with officials present.
Guilty players are believed to be members of the Varsity squad.
Guilty players have on t-shirts with their schools logo and name, etc.
Guilty players are not listed in the JV scorebook as participants.

Officials administer "T" for dunking. Guilty teams coaches argue that officials can not adiminster "T" against them since the guilty players are not part of the game roster.

Officials state that since guilty players are on the court with 'scorebook' participants that they must be part of the overall 'team' and illegal players at the time.

I feel the "T" was warranted, but he explanation wasn't very strong.

Was this situation handled properly?