helmet rule
 

I was asked -- "Is there a rule:

That a player can’t remove her helmet approaching home plate after a home run ? The ball is already dead (over the fence) and there is usually 12 girls with no helmets surrounding home plate when the player arrives. Absolutely zero risk to the batter – no ball is in play or in the playing field.

Last night – the girls put on a homerun straw hat when they hit home plate. Girls having fun – nothing malicious about it."

For NFHS the rule is not so much that a player can't remove a helmet under certain conditions, it's more that a player is required to wear a helmet while the ball is live and in live ball territory until the ball enters dead ball territory.

See Case Play 1.6.2 Situation A for a good take on the situation.

My quick answer, via email:

The NFHS rule is about live ball status and would be a just team warning if live ball.
Only the USA Softball rule with live ball is an out.

Clarified by:
as you said, it's a dead ball. My answer was that the rule is about live ball.

I am asked questions like this because I am the Rules Interpreter for our local association (NFHS & USA Softball).

USA 3.5.E Effect
 

Effect: Failure to wear the batting helmet when ordered to do so by the umpire shall cause the player to be removed from the game. Wearing the helmet improperly or removing the helmet during a live ball play and judged by the umpire to be a deliberate act shall cause the violator to be declared out immediately. The ball remains live. Calling a runner out for removing a helmet does not remove force play situations. Umpires should use discretion as to the intent of the rule concerning player safety.

My highlight. Also, a bit of a tricky situation could arise regarding force plays. Removing the helmet does not remove the force play.

Again, it would appear that if a player hits a HR, rendering the ball dead, it would be acceptable for the BR to remove her helmet.