We reported a few months ago about the “radio frequency identification” chips which are embedded within the new passports and loaded with digital information about the passport holder–mainly the same information found on the identification page. The concern with this chip is that it can broadcast this information to the wrong person.
According to an LA Times article by Jane Engle, the government claims the chip can only be read at a distance of 4 inches when the passport is opened. Others, however, claim that this range can be greatly increased with the proper equipment, thus turning American tourists into a walking radio station broadcasting personal information. One expert even claims that the signal can be used to detect an American passing by and set off a bomb, as illustrated by a YouTube video found here (although this is apparently a very improbable scenario).
Scared? You can always disable the chip using a very simple and primitive method described here. But of course, we here at Gadling would never condone such an action.