Maybe the Americans would do better at UTMB if it started in the morning instead of 6PM.
Why start a 100 mile race at 6PM? Starting it at close to dawn means if you finish in under 24hrs there's a higher proportion of daylight to nighttime running.
Like god, imagine flying halfway across the world, being jet lagged AF, and then running 100 miles at 6 PM. Forget the course/conditions, that alone sounds awful.