Penalty for Removing Batting Helmet After Home Run

[clodder]

This happend in a girl's softball league (10 y olds) in Toronto, Ontario but I assume that the rules for this are universal.

Batter hits a home run, and the bench empties to congratulate her as she is returining to the bench. Just before leaving the field of play, she removes her batting helmet as she is about to enter (within a few feet) the bench/dugout area, and the umpire calls her out for not having her helmet on while on the field of play

Was this a correct call? Should there in fact have been penalties for the other players congratulating her, i.e. being on the field without hlemets even though the ball was not in play at the time?

(I'm not an umpire so please be kind when answering.)