There were experiences in WWII where the plane crashed, crew survived and scrambled out of the plane and had to watch as all their survival gear burned in the wreckage. "survival vests" were born from those experiences.
Good point.
This Canadian trapper was pinned under his 4-wheeler for days. He had plenty of supplies strapped to the vehicle but he couldn't access anything that was not on his person.
Everybody thinks they can get to whatever is in their pack... until the pack falls over the cliff or floats down the river.