Hi, I don’t have their expertise but I backpack and camp a lot, including in some pretty hostile environments. I keep a pack of 12 in my trunk for emergencies. The answer is yes, they’re a thing and they work. They’re super lightweight. However, I wouldn’t want to use one unless I had to. They keep you warm by trapping all of the moisture and humidity from your body inside. This means you’ll feel clammy and sweaty if you use one for long. This is why they’re called “emergency blankets”.