We're all too familiar with the concept of technology as a double-edged sword, and wireless is no exception. In fact, the back edge of this rapier is sharp enough to draw blood. Yes, the idea of shedding wires and cables is exhilarating: we can go anywhere and still maintain intimate contact with our work, our loved ones and our real-time sports scores. But the same persistent connectedness may well lead us toward a future where our cell phones tag and track us like FedEx packages, sometimes voluntarily and sometimes when we're not aware.

To see how this might work, check out Worktrack, a product of Aligo, a Mountain View, Calif., producer of "mobile services." The system is sold to employers who want to automate and verify digital time-logs of their workers in the field. The first customers are in the heating and air-conditioning business. Workers have cell phones equipped with GPS that pinpoint their locations to computers in the back office. Their peregrinations can be checked against the "Geo Fence" that employers draw up, circumscribing the area where their work is situated. (This sounds uncomfortably like the pet-control technology, those "invisible fences" that give Rover a good stiff shock if he ventures beyond the backyard.)

"It they're not in the right area, they're really not working," says Aligo CEO Robert Smith. "A notification will come to the back office that they're not where they should be." The system also tracks how fast the workers drive, so the employer can verify to insurance companies that no one is speeding. All of this is perfectly legal, of course, as employers have the right to monitor their workers. Smith says that workers like the technology because it insures they get credit for the time they spend on the job.

Worktrack is only one of a number of services devoted to tracking humans. Parents use similar schemes to make sure their kids are safe, and many drivers are already allowing safety monitors to keep GPS tabs on their travels (OnStar anyone?). Look for the practice to really explode as mobile-phone makers comply with an FCC "E911" mandate dictating that by the end of 2005 all handsets must include GPS that pinpoints the owner's location.

The prospect of being tracked "turns the freedom of mobile telephony upside down," says Marc Rotenberg of the Electronic Privacy Information Center. His concern is government surveillance and the storage of one's movements in databases. In fact, if information from the GPS signals is retained, it would be trivial to retain a log of an individual's movements over a period of years (just as phone records are kept). An even darker view is proposed by two academics who wrote a paper warning the advent of "geoslavery'." Its definition is "a practice in which one entity, the master, coercively or surreptitiously monitors and exerts control over the physical location of another individual to routinely control time, location, speed and direction for each and every movement of the slave."

My guess is that the widespread adoption of tracking won't be done against our will but initially with our consent. As with other double-edged tools, the benefits will be immediately apparent, while the privacy drawbacks emerge gradually. The first attraction will be based on fear: in addition to employers' keeping workers in tow, Mom and Dad will insist their teenagers have GPS devices so parents can follow them throughout their day, a human equivalent of the LoJack system to find stolen cars. The second stage will come as location-based services, from navigation to "friend-finding" (some systems tell you when online buddies are in shouting range) make our lives more efficient and pleasurable.

Sooner or later, though, it will dawn on us that information drawn from our movements has compromised our "locational privacy"--a term that may become familiar only when the quality it refers to is lost. "I don't see much that will bring it about [protections] in the short term," says Mark Monmonier, author of "Spying With Maps." He thinks that that we'll only get serious about this after we suffer some egregious privacy violations. But if nothing is done, pursuing our love affair with wireless will result in the loss of a hitherto unheralded freedom--the license to get lost. Here's a new battle cry for the wireless era: Don't Geo-Fence me in.