I've been hit intentionally with a competitors whip previously - I beat her top student at the state championships on the first day of competition, on a mare. The next day of competition, I was out warming up next to my arena about to go in, and this woman (who is a very big name here unfortunately, mainly due to her $$'s thus ability to import every horse she rides) comes straight over on her stallion, knowing full well my mare was well and truly in season, side swiped me so her boot hooked on mine, then gave my mare a good whack on the backside. Mare obviously freaked out. I went straight into the arena, and said competitor continued to circle at A for my entire test. As soon as I finished the test, she moved on.
My coach was about ready to explode I think!!