The bold part says it all.
I would not let a 13 year old take my horse and train it.. for love or money.. unless I was there and they had shown me some ability on THEIR horse.
I agree with this. There are
some young people who do have an affinity for training, especially those that work closely with a trainer but they aren't exactly common. IMHO, if they can't even control their own horses, then there is no chance of them being able to successfully train horses for others but sometimes that is something that they have to figure out for themselves.
I know a girl that is very similar to the kids you are describing. Just a few years ago, when she was around 12, her grandparents bought her a green broke 3 year old gelding to be her next show horse. Because they doted on her and praised her constantly about "what an amazing horseman she was and how talented she was and what a great rider she was and she could train a horse to do anything", she believed them.
Well, it didn't take long for that gelding to start having "problems" like bolting and bucking. Go figure, right? Anyway, grandparents brought the horse to my Dad for training and after a couple of months, he had the horse going extremely well. Nice and collected and slow at all 3 gaits, nice flat topline, soft mouth, good stop, proper lead departures, etc.
They came to pick the horse up and Dad had the girl get on the horse so that he could describe how he'd been riding the horse and how she would need to ride him to get the best behavior out of him and she snapped back with "I know
how to ride my horse". So, Dad just stepped back and let her ride him her way.
That was in the early winter and that next fall, we saw her with that horse at a local 4-H show. She had him in training forks with a curb bit, he would bolt toward the gate every time they went past, he wouldn't pick up the correct lead, he was hollow and strung out and his stop was non-existent. I was disgusted by what I saw because I remembered what he looked like when he left Dad's house.
Unfortunately, there is just no cure for stupid and it's unlikely that you can do anything to stop them from training horses for others.
On a hopeful note though, perhaps they are just vocalizing on wishful thinking like most teenagers are wont to do. Saying that they are "going" to start training for others because that's what they want to do but they never actually get around to doing it, you know?