Over the past 15+ years, I've trained quite a few HS kids to ref low level rec games starting with 3rd grade. It's my opinion that the reason they are hesitant to blow the whistle sometimes is not because they don't recognize when they should, but that they are relatively self-conscious or shy and don't want to draw attention to themselves. During training, I work on building their confidence to blow the whistle and let them know that if they make mistakes, it's not the end of the world. I tell them to work as many games as they can and try to match them with veterans for most of their first season. This seems to help a lot.
Of course, the kids who express an interest in officiating aren't usually the type who are extremely shy in the first place, thank goodness. That makes my job easier.
I tell them the more they work, the closer they will eventually get to being perfect, like me.
