In our opening HS game, NFHS rules with no association specific language about bench conduct, one of our players hit an over-the-fence homerun and the players in the dugout went out to congratulate him, staying in foul territory near home plate. (I'm the team statistician but also the one who has read the rules most carefully.) The plate umpire told us that, because of a rules change two or three years ago, they should all be ejected for coming out of the dugout.
I think that Casebook 3.3.1 Situation CCC makes it clear that such celebration is permitted, provided the team doesn't interfere with the umpire. I suspect the umpire was thinking of the 2022 point of emphasis about over-the-top celebrations with props and choreographed moves and such.
But my question is about Rule 3.3.1.i: "A ... player ... shall not be outside the designated dugout (bench) or bullpen area if not a batter, runner, on-deck batter, in the coach's box or one of the nine players on defense." This doesn't appear to be restricted to a live ball situation and appears broad enough that an umpire could decide that home-run celebrations were not permitted. But it also seems broad enough to prohibit things like: players chasing down an errant foul ball, players going to the bathroom, or even having a 10th player warm up the left fielder between innings when the team is in the 3rd base dugout.
3.3.1.i seems almost redundant with 3.3.1.a except (i) would be about remaining out of the dugout and (a) is about leaving the dugout. But is there some live-ball provision I'm missing? Can this be used to prohibit home-run celebrations?