Don't take this the wrong way, I don't know if it works because where I am, I can't try it (no snow) though if I was somewhere with a good layer of snow I might try it by slowly increasing the time I spent outside with one WET boot (like if it was dipped into a puddle) and one WET sock (same dipping) just so that I would know for sure.. but the point is, if it does work, and you knew, you would have something you could do..
Let me ask this, if your boot is soaked in the snow and for whatever reason you can't make a fire or stop to dry it out, do you think adding more dry socks and then puting your wet boot back on really help?
I put it this way because thats the way I heard it, not to forget about your boots and the like, because they work quite well when they are dry, but in case your boots got soaked while out in the snow... Oh, the article I read didn't say your feet would be warm, just warmer (warm being relitive), warm enough to better prevent damage... but like I said, I don't know, I've never tried it and I don't have any way (short of takeing a week off to go to the snow, which I can't afford) to try it.