The day I got my NIS (SS) card, I memorised the number. I then put it in a sealed envelope and put it with the rest of my important documents.
The only important card I carry in my wallet is my bank card but that can be cancelled in a matter of minutes. Sure they can find out where I go to college, a few personal details, and even get a discount at the local game shop with the rest of the contents, but they can't do much more.
I remember when I was younger, some guys jumped out the back of a van at the end of our driveway with a gun. Most of us ran into the house but my brother was dumb enough to stay outside so he got thrown around a bit. Lesson? Do what they say or run away before they can get a word in.
If anyone came into my house, they can take whatever they want so long as they don't hurt me or my dog.... or even take my dog for that matter! Nothing in my house is worth getting killed over.