When I audited it several years ago I got a lot out of it without riding. I was able to take notes and then try those things at home slowly, at mine and my horse's pace. Having not done big group rides or shows, I personally wasn't ready for that type of situation.
Still haven't done group rides or shows myself, but I'm determined to throw myself in head first now (and hopefully that won't be at the hands of my horse).
A horse will only reach the level of it's rider.
I truely believe the only thing that improves a rider's skills and ability is riding.
It's like conquering ALL the scariest rides at Kings Dominion. I didn't do that until last year, that bunji jumping thing was the last one... I finally did it (and boy it was UGLY!
) but now I'll go back and do it again, without paralyzing fear. It takes a while to get to that point, but once you do, you you'll be amazed at the satisfaction you feel inside.
If you do the clinic WITH your horse, and you are successful in learning how to help your horse accept new scary things, your riding skills and confidence will move forward by huge leaps and he will be a much safer horse.