Well, if your clothes were burned off, you'd have second to third degree burns and be in shock pretty quickly. Plus burns to get infected if you survived the burns and the shock. In a cold climate, you'd get hypothermia and frostbite pretty quickly if you were naked. Even the wrong clothes can get you killed in cold climates.
These "survival" shows are not realistic, for a number of reasons. First off, the people in them are not going to die. If the producers of these shows allowed people on them to die, they could be charged with crimes. Negligent homicide, manslaughter, etc. Someone could die in an accident, but the producers could not stand by and let these people die if they failed to perform correct survival skills. People react differently when they know it's do or die as opposed to having a back-up where their survival is ensured. Law enforcement agencies won't allow a show where people would be allowed to die. And they probably take a peek at them from time to time just to see. Back to the do or die issues, I saw a guy who passed a three day Red Cross first aid course with flying colors. But when we had an industrial accident, he froze up and stood there watching an injured man bleed. So, actual reality differs from staged "reality" when it comes to human reactions.
This is just entertainment, such as it is. I'd be leery of anything "as seen on TV". TV exists to sell products, no more, no less. They'll do whatever it takes to get ratings that they can show advertisers, regardless of whether or not what is shown is factually correct. In an actual survival situation, the best and worst comes out in people and you can't film that at all when it happens. Take that plane that crashed in the Andes, for example. They had to resort to cannibalism to survive. Can you put people into that kind of situation and film that? Of course not. That was an anomaly where human flesh was the only food available to them and so they had to resort to that. But first, they had to be desperate enough to break a major human taboo about cannibalism. That is something that cannot be staged. Therefore, a TV show can't show you how far someone will go to survive or what they might have to do in order to accomplish that.
Another example. The Donner Party. Again, they had to resort to cannibalism. But you had to have "the perfect storm", so to speak, for that to happen. Wagon train tried to beat the snows, they didn't listen to experienced guides, they tried a questionable shortcut, they didn't want to wait, and so they got trapped. And the rest is what they ended up having to do to live. If a TV show tried to create this scenario, they'd all be carted off into federal custody and be looking at 20 to life prison sentences. But the Andes plane crash and the Donner Party are two prime examples of what happened in survival situations where people were dropped into them without proper gear and supplies.
Another thing. When you KNOW you are lost, that is far different from being "lost" with a film crew hovering nearby. The fear factor just isn't present when you can get "unlost" quickly by crying uncle and throwing in the towel. In a real survival situation, throwing in the towel means you lay down and die and every turkey vulture and raven in the neighbourhood show up for a free meal. Putting cash as a reward for success isn't realistic, either. It's far different from your own life being the door prize.
And as far as the nudity, need it even be said? It's typical Hollywood. Sex sells. They're trying to evoke something primal, but what they're evoking are the more unpleasant attributes of man's primal nature. Obviously, this is so. Or there would be two 55 year old men with potbellies naked as opposed to a man and a woman. It also involves some rather tiresome fantasies that go along the lines of, "If you were naked in the woods with (insert name of woman you think most attractive here), what would you do?" Indeed, need it even be said?
We are truly at an impasse with television, such as it is.