A backpacker's pack is, of course, nothing but a large survival kit. But I've read many accounts where people became separated from their backpack (or basecamp, vehicle, etc.) somehow, and then become lost, injured or otherwise get into difficulty.

This emphasises the importance of keeping your essential survival supplies securely attached to your person at ALL times when out and about, and also part of what makes Mr. Ritter's survival kits such brilliant and useful designs.

They can be buttoned or zipped safely into a pocket and largely forgotten about. But you can count on them being there with you when you really need them.