Since I switched to a combined training barn, I ride more in a "safety seat" and don't get hung out to dry when a horse refuses. On the other hand, I was out hunting last season and my 100 percent reliable bombproof mare actually FELL DOWN just cantering up a hill. We'd been out a couple of hours and had a couple of fast runs, so she was a little tired, and I think she hit a wet patch and her feet just shot out from under her. I rolled off her shoulder and was on my feet before she was. We both were fine, but the expression on her face was a study. She was highly embarassed.
I've been riding for 45 years - since I was 5 or 6 years old. I've accumulated a few injuries along the way - broken nose, torn ACL, bruised ribs . . . the only serious one in 45 years was a badly broken finger that basically had to be reassembled on the surgery table. It doesn't even ache when the weather changes, though, thanks to glucosamine/chondroitin tablets. And that didn't happen in the hunting field or on the cross-country course - I was working a big doofus of a Quarter Horse over a small grid and he tripped over his own feet and fell down.
I agree with you that Reeve was just incredibly unfortunate. I've shot off over the horse's head many, many times . . . about 20 years ago, riding somebody else's horse that was very heavy on the forehand, I came off four times in a one-hour lesson! (I didn't ride that horse any more.) It comes with the territory - but usually the consequences aren't that severe. On the other hand, I know somebody who sustained a severe head injury falling in the bathtub . . . there are no guarantees.
BTW, if you saw the film, is there any truth to the rumor I heard that he had his reins wrapped around his hands and so could not catch himself?
Sounds like we could swap war stories. I have had many accidents where I could have been seriously injured or killed but by the grace of God was not. I was foxhunting in Ireland(worked for one of the hunts there) and the hunt was galloping down a paved road. The horse in front of me slipped and went down and since we were right behind we fell over it. I jumped up and caught my horse, but the other person had his foot caught in the stirrup and his horse panicked and began kicking him. Luckily his foot came free and he was able to get back on. Neither the horses or us were injured after falling on tarmac at a gallop. I don't even recall that it hurt - probably the adrenaline. I also was hit by a pickup truck after my horse bolted into a road - I went into the windshield, bounced off the hood, landed on the road and walked away without a scratch. So I have been extremely lucky so far. The horse had 5 broken ribs. Since then I am extremely careful about riding near roads!
If you are going to ride, and especially if you jump, you are going to fall off. I think the biggest limiting factor for older riders is fear - kids just aren't as afraid. I know I did crazy things when I was a kid that I would never do now - like riding a cross-country course in Ireland bareback.