No, but it helps to keep your hair under your helmet 😂
No, it is not required for jumpers and a very respectable jumper, Kristi Vanderveen, doesn't ever wear her hair in a hairnet even in the grand prixs! It's pretty much up to you
If you don't have your hair tucked in, then you should have a really nice bun at the base of your neck, but still wear your hair net. Lower level shows it's not that important but if you get to upper levels it looks much nicer and clean. I've also seen people in trillium level shows just french braid their hair.
If ur Hunter Jumping u dont have to but usally competing A shows u should
At B shows it's doesn't matter but at A shows you should
No, but at big shows you should