Regards the survival blanket issue:
People are missing the point discussing quality at all. I think Dougs kit is better quality too. And it's no criticism of Doug's american made and sold kit, to say it's not the best one for a place it's not intended for.
You'd be better off with a bag than that blanket and the mega tough survival bags we use would be even better.
But even a poor quality item is bound to be better, than one that is simply not there!
In the UK where the most common hillwalking survival situation is surviving exposure; a bag is the thing to have if you could chose one item from either kit.
Since rucksacs aren't usually waterproof I simply tie off the bottom and use my bag as a sac liner. then you always have it with you.
The Sock