Embedding identity documents — passports, drivers licenses, and the like — with RFID chips is a no-brainer to government officials. Increasingly, they are promoting it as a 21st century application of technology that will help speed border crossings, safeguard credentials against counterfeiters, and keep terrorists from sneaking into the country.

But Paget's February experiment demonstrated something privacy advocates had feared for years: That RFID, coupled with other technologies, could make people trackable without their knowledge or consent.

He filmed his drive-by heist, and soon his video went viral on the Web, intensifying a debate over a push by government, federal and state, to put tracking technologies in identity documents and over their potential to erode privacy.

Putting a traceable RFID in every pocket has the potential to make everybody a blip on someone's radar screen, critics say, and to redefine Orwellian government snooping for the digital age.

"Little Brother," some are already calling it — even though elements of the global surveillance web they warn against exist only on drawing boards, neither available nor approved for use.

But with advances in tracking technologies coming at an ever-faster rate, critics say, it won't be long before governments could be able to identify and track anyone in real time, 24-7, from a cafe in Paris to the shores of California.

The key to getting such a system to work, these opponents say, is making sure everyone carries an RFID tag linked to a biometric data file.

On June 1, it became mandatory for Americans entering the United States by land or sea from Canada, Mexico, Bermuda and the Caribbean to present identity documents embedded with RFID tags, though conventional passports remain valid until they expire.

Among new options are the chipped "e-passport," and the new, electronic PASS card — credit-card sized, with the bearer's digital photograph and a chip that can be scanned through a pocket, backpack or purse from 30 feet.

Alternatively, travelers can use "enhanced" driver's licenses embedded with RFID tags now being issued in some border states: Washington, Vermont, Michigan and New York. Texas and Arizona have entered into agreements with the federal government to offer chipped licenses, and the U.S. Department of Homeland Security has recommended expansion to non-border states. Kansas and Florida officials have received DHS briefings on the licenses, agency records show.

The purpose of using RFID is not to identify people, says Mary Ellen Callahan, the chief privacy officer at Homeland Security, but rather "to verify that the identification document holds valid information about you."

Likewise, U.S. border agents are "pinging" databases only to confirm that licenses aren't counterfeited. "They're not pulling up your speeding tickets," she says, or looking at personal information beyond what is on a passport.

The change is largely about speed and convenience, she says. An RFID document that doubles as a U.S. travel credential "only makes it easier to pull the right record fast enough, to make sure that the border flows, and is operational" — even though a 2005 Government Accountability Office report found that government RFID readers often failed to detect travelers' tags.

Such assurances don't persuade those who liken RFID-embedded documents to barcodes with antennas and contend they create risks to privacy that far outweigh the technology's heralded benefits. They warn it will actually enable identity thieves, stalkers and other criminals to commit "contactless" crimes against victims who won't immediately know they've been violated.

Neville Pattinson, vice president for government affairs at Gemalto, Inc., a major supplier of microchipped cards, is no RFID basher. He's a board member of the Smart Card Alliance, an RFID industry group, and is serving on the Department of H