Survival Training is full of Myth's like "Don't Eat Snow" to "Don't Sleep in the Cold". I have often wondered at how bad our teaching was/could be without proper research. Modern Medical & Survival Research has changed may of our methods over the last 40 years if you look up the what and why, often advice has changed radically, once the laws of physics and physiology have been applied to the problem, instead of "Assumptions".