I cant see this being of much use.
A blanket or similar can not stop someone being killed if heavy debris falls on them.If a heavy roof beam for example falls, it is liable to crush the victim to death, and no flexible "shelter" would save them.
Neither can it stop the victim being picked up by the wind and subsequently being thrown with lethal force against structures or the ground. Indeed this product might Increase the risk by acting as a wind sail or kite.
It would give some protection against small fast moving projectiles, not just bullets, but also broken glass etc.
If protection against a mad gunman is in fact the main idea, then as others post "shoot me red" is not a good choice.
A proper tornado shelter should also last many years without significant furthur expense. These blankets will get lost, stolen, used for other purposes, and presumably require periodic replacement at significant expense.
After a few years without a tornado, I have little faith in the blankets actualy being on hand for instant use when needed.