I've studied survival intensely all of my life, practicing whatever seemed practical. I've yet to see anyone on this show who knows more than Boy Scouts knew when I was a kid The producers must pick them carefully for their ignorance. They all "think" that they want/need a fire in their shelters and half a dozen have burned their shelters as a result, one gal did so twice! :-) Almost all of waste way too much time on their shelters and never have one that's worth a hoot. Because they "think" that they want a fire, they have to leave lots of vent holes, choke on smoke and of course, freeze their butts off cause all the heat goes out the vents.