The first I ever heard of this was of that show, but I never saw the show. Last year someone posted a link, in the hammock forums I think, to a video of a guy at a gathering called the "Butt Freeze" (or something like that) campout in MN. But in that video, he never really got his fire going before dark, so you never got any idea of what it would really do.

Jim, (ULhiker here), sent me the link to the video I referenced a month or so ago. It doesn't show the shelter very well, but he does demonstrate that it works.

Tom, the shelter is almost exactly like what you linked to.

I took the shelter down this afternoon so I can play some more with attaching the mylar. Here's a few pictures of it before I did: