Some people do but it is primarily designed for a specific purpose, your legs will not be in the correct position to jump or extended paces but that doesn't stop people doing it.
Oz
I have a horse I always ride in a dresage saddle. Our main game is dressage, but we hack 5 times a week (no facilities at home) and sometimes jump up to an earth shattering 2ft!
Thanks guys, Unicorn that's what I was wondering about. I don't jump but hack out, found a really nice saddle to accomidate Blue's pathetically-high withers, but its a dressage one. Figures lol.
I had to exercise a fit hunter in a dressage saddle as its usual one was being repaired. it was great until we started the faster work cos in Gallop it stopped me from hovering over the saddle due to it's shape so I had to stand up - oh boy it was agony and soooo knackering. On the other side of it, I used to ride another horse in its dressage saddle and could even manage small jumps - though when it refused suddenly there was nothing to help me stay on either...