But I’m self-aware enough to know that if you could go back in time, and ask me to explain the lookback rule when I was coaching DD’s first-year 10U Rec team as one of two volunteers who were willing to put in the time, I’d probably have gotten it wrong.
If you fully understood lookback after the first year of 10U Rec, you were way ahead of many people, including me.
At younger ages, I really valued umpires who made the effort explain the application of some of the more arcane rules specific to girl's FP. I never liked seeing a game stop for a convention, but greatly appreciated some between-inning education.
In a 12U game, an umpire told me mid-inning that our catcher was blocking part of his view by rising up a bit during some pitches. Really appreciated that as well.
I don't think anyone wants an umpire "coaching" players on their technique, but a quick explanation to a player of a call, or the education of a beginning pitcher/catcher on the rules isn't something to get worked up over.