I didn't watch the video, and I have no doubt that it does work. You could never crawl through the country that I like to hunt without making 100 times the noise that you would make just stepping through it.
But, I have hunted heavily pressured deer in desert country and used a leafy suit to walk right up to deer. With a leafy jacket and hood on I have stood up from a ground blind and walked, bent over, within bow range of does that I did not intend to shoot. In the same area I spotted a buck in the open. There was no chance of a stalk as it was wide open. He winded me and was warry (sp?). I did the bent-over walk thing and used a grunt call, bow in hand, and closed the 200 yds yards to 60 yds. before he trotted off.
And many times, in all kinds of conditions, I had thrown on the leafy hood only and had much better success than if I had not used it. Its about breaking up your outline.