My senior moment senile read of the current rules tells me hunters (and other divisions as well) have to wear a helmet whenever the class involves jumping, and that JUNIORS in hunt seat need to wear a bucket on their haid any time they are on a horse at the show grounds.
Pat, judging by what I read on the internet about the double bridle (granted, this is mostly from people who don't do dressage, do a lower level of dressage, have never brought up a horse through the levels, or whatever level they ride at, they do it largely without legitimate instruction), few people, at least from that demographic, will use the snaffle at the higher levels -
'The double bridle is what allows the rider to equalize the weight born on both hind legs'
(this is done in the schooling of the horse from the day he is broken to saddle, through straightening and strengthening work - in the snaffle bridle)'
Why would ANYONE EVER school an upper level horse in a snaffle since the double is what creates collection?'
(collection starts long before the double bridle is put on - the double bridle cannot 'create' ANYTHING that has not already been taught to the horse and the muscles created systematically and progressively, so that the horse can do it. The double bridle is for refining the aids and is a traditional test of skill)
'NO ONE EVER schools a horse in a snaffle once they get the horse in the double bridle'
(Reiner Klimke even warmed his horse up at major competitions in the snaffle bridle, and most legit dressage trainers only train even a Grand Prix horse, part of the time in the double bridle)
'The double bridle gives more control'
(actually, no. The double bridle is not for brakes, nor is it able to create anything the horse has not already been trained to do!!)
As one trainer said (JOKINGLY), 'VY do you sink you need zu dubble bridle for BRAKES - ven you are in zu arena, you have a VALL - RUN ZU HOSS INTO ZU VALL EFF you NEED Brakes - ZAT vill shtop him!!!!'
'The curb bit sets the head/produces flexion/or whatEVER, and the snaffle bit raises the head'
(Wels in voice of Minion from 'Despicable Me': 'WHAAAAAT?' Wels cannot understand why someone can't flex or bend a horse with a snaffle bridle, or anything else, AND...Wels cannot even continue, Wels needs to go take an antacid, a decongestant, and do some deep breathing and visualization of blue skies and fluffy white clouds, and get a lengthy massage from Blond Hans)