If I had a high-dollar stallion, I'd be either doing AI or hobbling. Not taking chances - I've heard too many horror stories from breeders who have had stallions loose function in one (or both!) testicles or been otherwise injured by mares who can't make up their minds. When I handled mares for a small-scale breeder years back, I never actually hobbled any; if they wouldn't stand for it, they were generally either just coming in or just going out of heat. The only mare I ever had a SERIOUSLY problem with was the biggest b*tch in the world. She'd be fully in heat, receptive to *cough* foreplay, but as soon as the stud would go to mount she'd lash out with both hind feet as hard as she could. Clocked him in the head once so hard that it was a challenge getting him to cover the next mare who came in heat (of course, after a couple of coaxed repetitions he remembered how fun it was and got over it.)
The vet ended up telling us that she was small and maiden (not surprised) and was probably just hurting a little. Sedatives + painkillers for a couple of covers and she never gave us a problem again.

I don't think hobbling is "rape," and I think it's almost a little anthropomorphizing to assign that word to any breeding behavior in horses, unless it's someone trying to force-cover a mare that isn't in heat. (Dumb Idea by BYB #518.)