Iforget who it was said "Horse's are rugged sport". We can put year's of training and riding into a horse, and they are still a living breathing being that can get frightened by something or simply make a mistake. A 58 year old man from Germany was killed the other day and a young boy injured after coming off their "dude horse's" during a guided trail ride in Yellowstone Park. The horse's were startled by some bird's. IMHO the best we can do is put as much time into our horse's as we can, and be honest as to our ability as rider's.