Many people with little experience do not prepare properly, regardless of what they were taught. Many also do not recognize the signs of dehydration and hyperthermia. Many, when they do feel something wrong, feel the need to push through, tough it out so they don't look bad in front of their friends. I have seen this many times in many different situations. The adult volunteers should have been more thorough in their pre-hike checks and in their attention to how the kids were doing. Kids don't know, they have never experienced it. Their first instinct is to hide it. Yes scouts are supposed to be learning and taking more responsibility, but even in the military there are certain checks done on troops no matter what their age.