Guidlines are just that- a guide. Survival is proactive. Take the case of a man lost and eventually found dead.He stayed in one place waiting rescue,making journal entries that staying in one place was bad advice. He never made any effort at signalling. The infinite variables of individual fitness, mental and physical, external conditions etc.will always make this a mean average. The important thing is for people to start surviving NOW, not 72 hours and 2 minutes because the search teams haven't shown up within the statistical 3 days.