I love horses as well, and have enjoyed many a ride on the beach in my hometown but always after hours (after 6 pm) or very early, before 8 am. I have seen them at a canter with too many people on the beach in Jamaica. Even at a standstill there is liability if a visitor runs up on a horse and startles it. Maybe designate a stretch of beach that is not so heavily in use? Do they give trail rides on the beach or are they soliciting for local riding stables? Or are they more like pony rides where they just lead an inexperienced rider around a little bit? Poop does need to be cleaned up!