[QUOTE=Sticky Situation;9042848]
I really doubt that an upper level horse would be ruined for life because an amateur with poor timing once incorrectly asked for a lead change. The horse may need a bit of reschooling, but it’s pure DQ drama to contend that it would be ruined for life.
A horse that had a true traumatic experience - a bad crash, etc, is a different situation. If the rider became abusive and inflicted severe pain during Tempi changes, that might qualify. But being a bit confused by subpar riding isn’t really so traumatic as to ruin a horse for life.[/QUOTE]
I agree with this. IME, most horses, even highly trained horses, will revert to whatever they find easiest to do if not ridden totally correctly. Be that not bothering to collect themselves or trot along rather than pick up the canter, or whathaveyou. If poor riding ruined horses, there would be no saintly school horses to teach anyone on. And I would venture a guess that a lot of them have a lot more buttons than their beginner riders ever realize.
Something truly abusive (like being spurred bloody) or traumatic (like a crash) might ruin a horse, but I think horses on the whole are pretty forgiving and most of them can overcome that, too, with the right training.
Now whether or not you WANT to allow lesser riders on your advanced horse is another question entirely.