the guy (Bear Grylls) said this

Yeah, THERE's yer problem, right there. Actual survival experts have a special term for people lost in the wilderness who follow his tips: dead.

He's showing off for TV, nothing more. The basis of his survival training (and most likely the reason he always seems to be in a hurry to get places) comes from him taking the Brit military version of what we call SERE training: Survival, Evasion, Resistance, Escape.

In the military, students are taught that when they land in the wilderness, whether it's by crashing in a plane or escaping from a POW camp, the first order of business is to get the hell outta Dodge pronto, because there are probably guys with guns chasing you. That means that military survival tactics are a lot more tolerant of taking risks, because the cost of taking it slow might be your capture or death. In SERE, the whole idea is to KEEP from being found, because the people looking for you are probably not your friends. That's the "evasion" part.

And that's what Grylls seems to be demonstrating a lot of the time. But even at that, he's showing off and taking WILDLY stupid risks. The only reason he isn't dead is because his crew scouts all this stuff in advance, has local experts as advisors, that kinda thing. So when he dives off the top of that waterfall into the pool below, he already knows that it's deep enough, and he's not going to land in foot-deep water and shoot his spine out the top of his skull.

Oh, and then he takes a helicopter out and spends the night at luxury wilderness lodges. It's all staged.

In civilian wilderness survival, just about everything is different. You WANT to be found, so you do everything you can to facilitate that. Just for starters, in some cases, the best strategy is simply to stay put where you are and try and make yourself visible as possible. That works when you know that you will be missed and people will come looking for you very soon. If you keep moving, the rescuers are chasing a moving target.

But in the cases where you DO have to get out on your own, there are a variety of strategies, depending on the circumstances. Ideally you would have positional awareness of approximately where you are and a compass, so even if you don't know exactly where you are, you might know that if you travel west, you will HAVE to hit the road eventually.

But failing that, and in lieu of even having a compass, you need another plan. And this is actually the most common type of wilderness survival situation. Most of the people who get lost in the wilderness are NOT well-equipped hikers with maps and plenty of gear, they're day hikers who are going out for a "short, hour-long hike." So they don't take a compass, a map, water, or proper clothing. Then they take a wrong turn and walk for half an hour before they realize they're lost.

Next thing you know, it's getting dark, maybe it rains, they're boned. If they're found at all, it's usually in poor condition 2-3 days later. Bonus points because they're probably wearing cotton clothing, which wilderness S&R types call "death cloth." When cotton gets wet, it STAYS wet for a long time, and when the temperature drops a little and you've got a sweat-soaked T-shirt on, it sucks the heat right out of you and you die of hypothermia.

So, the river thing. In general, if you have no other viable options, it's a reasonable strategy. In almost all cases, following a river downstream will eventually lead to signs of civilization. But it's that "eventually" that's the bitch, you can't just blindly apply the technique, you have to think about where you are and what is the most likely direction of rescue.