The LA Times has an article on a proposed state statute regulating government use of RFID for tracking people (Not Letting Chips Follow Where They May). The basic concept is probably a good idea, but I'm not really sure that this legislation is the best way to go about it:

Rather than an across-the-board ban, the amended bill would forbid state and local governments from mandating radio-frequency ID technology in driver's licenses and in student ID, health insurance and public library cards. The bill would not limit private industry use of the technology.

With a few exceptions, governments could use the technology in other forms of identification so long as they included at least three protections, stipulated in the amended bill:

•    They must make sure the information is disguised with a unique identifier. A person's name, address and birth date, for example, would be represented by a number.
•    State and local governments would have to encrypt that unique identifier or scramble it in some way so that only a person with a code could link the identifier with the original information.
•    The cards must not transmit information to a reader until the machine verifies, perhaps using a secret password, that it is authorized to accept the data.