All good points! With reference to the rider on the lame horse- we should absolutely put the welfare of the horse first; however, you hunters have that wonderfully vague "serviceably sound" clause that always made me wonder if the judges are supposed to be veterinarians too. Still it amazes me that someone would continue to compete a horse that they knew the judge had noted as lame.
Katie, you make a wonderful point: the notation of "serviceably sound" in the hunter division can open up a whole can o' worms from the judge's perspective. For example, only the higher divisions of hunters at rated shows are required to jog for soundness anymore. That permits the older, creaky senior citizen horses to still compete at the lower levels, where their expertise and safe judgement are treasured by beginner riders. But being a little stiff due to being an older horse is one thing; outright lameness is something else. I agree: a judge sometimes gets put in the uncomfortable position of proclaiming that a particular horse is L.A.M.E. and should be withdrawn. That happens only rarely, fortunately! But personally I don't have any problem protecting our four-legged beasties, even if I have to confront a disgruntled owner or trainer.