Skippy! is cute as a button with verbal cues from me =)
Since he didn't have the build to jump as a profession, we just jumped for fun. I don't think we ever went higher than 3 feet but it was always a good time for him =) Anyways, where im going with this is... I would actually say "Hup!" where I wanted him to jump. I think it helped him initially make the connection for when to jump the fence. This also actually proved helpful out on the trail, because he wouldnt jump one of those little baracade things (like 1 1/2 feet tall, to keep dirt bikers and ATV people out of the trails) As soon as I said "Hup!" he stopped jigging at it, and jumped it (granted, i think he finally cleared it by 3 feet. It didnt help that there was a puddle beneith it, lol!)
When we used to Barrel Race (again, he didnt have the confo. for it, so we just did it every so often for fun. He just enjoyed running full speed, i never made him do the turns) I used to get him psyched as we got in the arena.
He would walk in all fine as if he were participating in a Walk Trot class, then I'd start getting tight in my seat and start semi-whispering stuff like "You wanna go? Get pumped. We're gonna run. We're going to run FAST." and he would jig a little bit and sorta "hold" the jig each trot stride (very pretty, lol!) then as we would get to the side of the arena with the timer on it, i'd go "You wanna go?" then raise my voice to a normal volume and repeat "You Wanna Go?!" Then finally in a semi raised voice i would say "YOU WANNA GO?!" by that time he'd start jigging in place, knowing I was about to give him the final cue.... "THEN GO!!!!" and with that he would pop a wheelie and TEAR off! His back legs moved so darn fast it would lift up the front end, LOL!
Every time we would turn a barrel I would yell "GO GO GO!!" and he would tear off again. finally on the last barrel (depending on the course) I'd start yelling "GO HOME RUN RUN RUN!!! HEE YAA! GET GET GET" and he would run his little heart out. I never used a whip, nor spurs.. and i raced in a D ring snaffle :p I actually beat 2-B division riders (if thats what they're called) with my Wonder Horse <3
Anywhoo.. i guess where i'm going with this is, Skippy! loves verbal cues. It helps him get pumped! Joey on the other hand does not like them. Its definately something that has to be worked into them though. I think that your friends experience may have just been a flook =) It may have been the last thing to make that horse finally realize he had to go over the object.
I'll not comment on anything else though, as it wasn't asked for in the original post and I believe everyone else covered it for the most part ^^