Nobody said he/she would behave like that in case of emergency.
We would only see reasons why people would behave like that beyond pure dumbness.
Regarding my personal philosophy... I always used to have my passport only on the body, however I definetily approve that I would most likely be shelterless in some parts of the world without CC, so I'll add one in future - the whole wallet would be to cumbersome.
Not needing medication, I see this as a big issue, though. You can see the amount some people carry at security check. I can see why people would not want to leave without.