Hair, IIRC, at a all breed association circuit we showed at, they hand galloped the Arabians in Western Pleasure. They sure did in Native Costume... :)
They ALWAYS gallop in Arab Native Costume, the wilder and faster the better. Everyone hoots and stomps feet in the stands to see just how hyped up they can get all the horses. Me in those silky pajamas on a rather satiny seat I was lucky to stay on, and everyone else was in the same boat. :~)
I can recall a few times in very large classes at Arab shows that the hand gallop, which was required, was kept short just because the arena wasn't big enough to have that many horses trying to gallop.
I think you're right to try to teach good sportsmanship, it's not good for her to think she's been cheated if she doesn't win every time. But a grandpa wants to say something nice and praise the job she did... I hope he understood the subtle difference.