Horses go 25, 50 or 100 miles just because we ask them to.
Can there be anything more noble?
Our only obligation is if we are going to ask, then we must prepare them and
help them through the day (and/or night).
If we don't prepare them... well, even my Chihuahua knows the answer to that.
Endurance riding is not that complicated...
Only when the horse's nature is overridden by human nature.