Radio-transmitting microchip tags -- also known as RFIDs -- are everywhere. New credit cards that work by being waved at a cash register use the technology. Governments are considering putting them in drivers' licenses, passports, and other documents.
While that could mean more convenience, the changes could also mean that your wallet could become a mobile radio transmitter, spilling information about you to anybody with the right kind of scanner and a good antenna. Privacy advocates say RFIDs present new risks for identity theft, electronic stalking, and other losses of anonymity.
So they've pushed the California legislature to pass legislation to guarantee people the right to turn off personal information being transmitted by their drivers' licenses and other documents. The "smart card" industry calls this overblown paranoia, and they're scrambling to keep the laws from spreading around the country.