First of all, I've heard from so many trainers, barn owners, etc etc that ARIA and like organizations are nothing but a waste of money because you basically just pay to have a certificate. 1) you don't have to be that good to be approved. 2) they don't do anything to improve the quality of instruction. It's basically, a place to pay for a piece of paper. In fact, I've been to their website and there is ONE trainer in my entire state that's "Certified". And she's a joke. None of the incredible, nationally known, even grand prix level (riding AND teaching at grand prix level) trainers are on the list.
No, her form isn't perfect. But it isn't horrible and it's functional. Just because you're a trainer doesn't meant that 100% of all of your jumps are perfectly done. I'm often complimented on my form over fences but kids at the barn have taken shots of me that I'm not proud of! Plus it's hard as a trainer to continue to have impeccable equitation. You'd be surprised at how easy it is to pick up a few sloppy habits here and there without eyes on the ground. I know very very few trainers who have the luxury of someone watch and coach them. Not saying it's ok to be sloppy, but still.
Plus, just because she's not jumping 3"6 in this picture doesn't mean she can't do it or teach it. I can jump 3"6 but the majority of the pictures of me jumping are at shows where I'm competing at 2"3 or 2"6. 95% of what I jump are either ponies or green horses and I don't have a lot of pictures of me jumping anything else. When you're a trainer you don't jump for yourself anymore, you jump what's best for the horse you're on and sometimes that's a lot lower what your capabilities.
George Morris says that you should never teach more then what you've done yourself. Either do yourself now, or HAVE DONE in the past. I personally think it would be very difficult to teach if I didn't ride regularly. But I know an older trainer who basically runs the rated show scene in her part of the state, who's well into her 60's, walks with a limp and doesn't ride anymore. Her clients are EXTREMELY educated, functional and beautiful riders. If I was looking for a trainer I'd go to her in a heartbeat. I have a friend who starting at 4 y/o was showing (and winning) and Pony Finals, Devon, Indoors, etc etc. At 8, people were paying her to break ponies for them. By high school she was doing the Level 5 and 6 Jumpers (which is just under grand prix). She is an incredible rider. She has an impeccable eye for a distance. She can get a horse to do anything happily. But she is a terrible trainer. She has a lot of knowledge but can't teach it well and absolutely no eye for a rider! She can't look at a rider and tell what's really going on and how to fix it. It's weird. Her students don't ride well. I wouldn't go to her to teach me.
Anyways, I could go on and on. I guess I have a lot of opinions about this, haha, but i'll stop now!