Zipping past Fisherman's Wharf, Chris Paget's scanner downloaded to his laptop the unique serial numbers of two pedestrians' electronic U.S. passport cards embedded with radio frequency identification, or RFID, tags. Within an hour, he'd "skimmed" four more of the new, microchipped PASS cards from a distance of 20 feet.

"There's a reason you don't wear your Social Security number across your T-shirt," Albrecht says, "and beaming out your new, national RFID number in a 30-foot radius would be far worse."

But Gigi Zenk, a spokeswoman for the Washington state Department of Licensing, says Americans "aren't that concerned about the RFID" in a time when "tracking an individual is much easier through a cell phone."