Following on from the aggression post, it is easy for horses to acquire labels over time. By working with them sympathetically even long standing behaviour can be completely extinguished although for some horses it will remain a default position which could re-emerge if things go awry.
There are also lots of labels for different types of horsemanship and the phrase "natural horsemanship" can cover a real multitude of techniques, some of which (many?) bear no reemblance to nature at all. It is so important for every person making choices on behalf of their horse to read the label first and then to soak if off and take a really close look at the actual contents; not just philosophies and concepts being relied upon but their practical application. I am very wary of techniques that purport to be all about love and libertyfor the horse when in fact they are about mental constraint and physical abuse. If your trainer tells you it is necessary to put your horse on the floor in the name of natural horsemanship or submission then please walk away (and take your horse with you). It is neither necessary or natural and is more about the trainer's ego and need to dominate than your horse's best interests. I have recently been told that at one natural horsemanship ranch there cure for separation anxiety is to tie it to a tree for two days and nights completely alone with no feed or water so that it could deal with its fears and be pleased to see its owner when they rescued it! My concern is that there is just as much nonsense, cruelty and dominance carried out under the banner of natural horsemanship as in any other school of horsemanship and plenty of room for charlatans. I don't know which is worse, never becoming aware of how horses really think or being totally aware and then abusing them with that knowledge. Once you know how they tick you know how to take them to the brink.