Have you looked through their "tips" on survival? I'm specifically referring to their advice on making fire in the wilderness.

The three methods they list are

1. Tin containing char cloth, plus striker and rock.

This is method is of course effective, but to make charcloth you need fire already. Also, making the charcloth probably requires the use of a tin. Since they're going into the wilderness with just a knife, (which would only fulfill the striker requirement)this method is only partially effective. Plus you still need to find a rock to use (quartz or flint).

2. Bottom of pop can.

If you can find one, seeing as you only went out into the wilderness with just a knife.

3. Fire with ice

Oh come on! Are these guys serious? I know this has been done before, but it's not a serious survival method for creating fire.