This has turned into a pretty interesting topic to follow. Part of endurance riding to me is dealing with situations and circumstances that come up on the trail. Cold or frozen water is a perfect example of having to ride to conditions presented. I am sure a lot of horses had issues out on the trail with not wanting to drink. I know my horse would have. I remember reading years ago about a very successful endurance rider's crew heating up stones in the vet check to put in their bucket of ice cold drinking water to make it more favorable for the horse to drink. Last October, I was at a 100 mile ride which was also in New Mexico. The weather was quite warm and on one of the loops the water tank that we passed was completely dry. It was the only water on that loop[. It was obvious that ride management was not at fault as it had been filled the day before and had probably slowly leaked out. Ride management also made an effort to get more water out to riders once they were aware of the situation. But on the longest loop in the hottest part of the day, some riders had to manage their horses and adapt to new ride conditions. Again, to me this is just part of endurance riding. Part of our responsibility is dealing with "conditions" presented on the trail. Sometimes dealing with these conditions means that it may be in the best interest of our horses to "pull" them at the next check because of situations like these if we were not able to successfully manage them through a particular situation.
I had planned on going to NYNM so this does interest me. One of the differences I see with this ride is that many of FEI riders were trying to earn COCs, place well for ranking, or complete in a certain time. It is hard enough to try to finish 100s in under 10 hours when conditions are ideal and the course is designed to allow this kind of finishing time. But when circumstances like weather, frozen water tanks, footing that changes as more horses travel through the course, etc. are thrown in the mix, it makes it much more difficult to attain the goals one sets out to accomplish or is expected to accomplish. I know when I am riding with goals that include a speed factor my margin of error is less so coming across a dry water tank when you are expecting water or coming across a frozen water tank (or really cold water) can or will change the entire game plan.
An interesting discussion for me would be the expectation that at rides that are actually promoting themselves as a "race" like FEI rides do, should those managing and promoting this type of an endurance ride assume more responsibility to assure that "race" conditions are as ideal as possible so riders can safely try to accomplish goals like COCs, rankings, etc? I would assume that ride managers would want to see as high a completion rate as possible at these types of rides. Regardless of the lower completion rate in 100s compared to other distances, I do find it interesting that on a flat ride with non technical footing that the completion rate would be in the 30% range. It just shows how one issue like temperature can skew completion rate on a course designed to be relatively easy. I believe I read that the FEI completion rate was around 27%. This isn't a judgement call on this particular ride or the ride management or even this kind of riding. I just know that if I wanted to and was expected to get the fastest performance out of my horse, I would attempt to do it in as ideal conditions as possible. And if I were to have to travel a fair distance like so many FEI riders have to, I would want assurances that these ideal conditions were in place and that attaining my goal was even possible on the course designed. In relating this to other sports where speed is the most important factor, conditions like footing, temperature, wind, etc. are most important deterring the ideal conditions for a "fast" performance.
I guess it really goes back to what Ranelle posted earlier about two different styles of endurance. In endurance riding, dealing with circumstances that occur on the trail are an expected (or should be an expected) facet of the sport and riders are expected to deal with them. In endurance racing, I am not sure that it is realistic to expect riders/horses to accomplish set goals such as COCs, ranking, set times for 100s, and deal with the natural or non natural circumstances that can occur on a course.