A little more on RFID

I got a terrific response to my questions in my previous post on how to disable an RFID chip. Mostly from The Disgruntled Chemist, whom you should all go read if you don't already. He knows a lot about beer and other stuff too.

While I was ponderin' all this technical shit, two things (almost at the same time!) popped into my head:

1) I guess in a pinch I can just carry the RFID-laced ID card in my tinfoil hat. "Curses! Tinfoiled again!", and

2) How do you detect an RFID whose presence in your pocket or in your head may not have been divulged by its sponsor?

I will now return you to Earth-based programming.