I still think some people are misinterpreted the show. The show is for hikers, hunters, backpackers who get lost in the wilderness. It is NOT for survival experts. I remember when I got lost on a hiking outing with only my day pack. The trail we were suppose to go on was flagged everywhere with flagging tape I am suspecting from hunters in the fall. Well to make a long story short, it was only a day hike. I had my SAK, matches, jacket etc but we ran out of water in the warm spring day and I hiked around for about 8 hours without a drop of water - I only brought water for the supposedly 4 hour trail - about 2 litres, my standard I bring on every hike. Well needless to stay, I felt lucky to get out about 15 hours of wondering in circles but it made me think. I have never been lost before and even with a fire, it would have been very difficult to boil water without a metal cup or pot. Plus, when I go out into the wilderness, I always carry a stove, pot, tent, etc so I do not have to make a shelter or hunt for food. I believe it is environmentally more friendly that way.
If I fell into the water and lost my gear and only had my knife, I would be in the same "do not know what to do" situation. Everything would be new knowledge to me since I have never made my intention to hack my own shelter from a oversized blade. I would probably drink from standing water if I was lost from many days. Beats dying on the spot.
And for those "be prepared for everything people", I use to be one until I discovered that planning ahead and lighting up your load is like finding Nirvana. When I lightened up load, I could hike an 22 km trail in 4 hours unless I am with a person that carries 3 knives, 4 pots, and and a gun. Then I can only travel about 8 kilometres while grinding my teeth all the way!
So how can you boild water with a fire but without a metal cup? Les did show us to use hot rocks in a hat. What are the other ways?