It turns out that when you're down to your last moldy hunk of bread and giardia-laced mud puddle, letting it all melt away in a cloud of smoke for a few precious moments can mean the difference between giving up and giving the rat (eating) race another go. If history has anything to say, it's more common than you think for people to happily give up MREs and gunlord harems in return for hastening their ends with carcinogens wrapped up in tidy paper packages. In traumatic situations like war, cancer sticks are often valued more highly than food. Even in the current (more or less) pre-apocalyptic global economy, cigarettes are one of the stable forms of currency.
This group stresses being able to stay alive for indefinite periods in life-threatening wilderness scenarios, including plane crashes, shipwrecks, and being lost in the woods. Concerns are: thirst, hunger, climate, terrain, health, stress, and fear. The rule of 3 is often emphasized as common practice for wilderness survival. The rule states that a human can survive: 3 minutes without air, 3 hours without shelter, 3 days without water, 3 weeks without food. 
Every year in the US about 150 people die while out and about in national parks, more than 1,000 die in hunting-related incidents and thousands of backcountry enthusiasts get in deep trouble and require a Search and Rescue team to save them; with dozens of those folks dying while awaiting rescue. Most fatalities are the result of poor preparation. Bad weather descends and people get lost. They wander without water or shelter, often injuring themselves in the process. If they survive they often suffer frostbite, hypothermia, dehydration, trench foot or some combination of them all.