In showjumping your body is 8 feet above the air, wrong step. Horse falls. Back broken:dead
In Eventing your horse has too compete 3 days in a row, the middle day is over a long course of unmovable, wide fences, over different terrain. Horse missteps, you die. Horse hangs a leg, you both flip...and die.
In all sorts of other riding activities, you're trying to control a 1100+pd animal. That may or may not want to play that day. Resulting in disasters.
I've had a horse rear up on me(stand on hind legs), and PURPOSEFULLY flip over...
"When the sun rises in the west and sets in the east, when the seas go dry and mountains blow in the wind like leaves. Then he will return, and not before."