THIS.

There are many,many people walking around with NFC, GSM, CDMA, WiFi, GPS, iDEN, WiMax, etc... chips that have faaaar better range than a passive technology like RFID. I'm not sure why people aren't up in arms about this. People driving GM vehicles, you know OnStar still works even if you have not subscribed to the service, right? People with Hyundais, BlueLink remains active as well, regardless of your subscription status. If you truly are afraid, you should get rid of all electronics with the ability to connect (ad-hoc or infrastructure ) to a wired or wireless network and move into a Faraday cage.