Aside from making driving easier, the on-board electronics revolution has given some people a new direction in their lives. Unfortunately, it could take them right into your bedroom or living room.

These people are GPS thieves. When they steal your device, they sometimes get more than just an electronics item they can sell for $100 or more on the street. They get your home address.

With the push of a button, one common navigational feature, the home setting, fully automates the process of directing you to your home -- a convenience that burglars and stalkers are sure to appreciate. It's enough to turn your free-floating anxiety about data theft into full-blown paranoia about home invasion.

The possibilities seem endless. The units' presence in a vehicle like Lexus or a BMW, for example, could give thieves a clue to a much bigger haul at the owner's home. And if they steal the garage door opener, too, they may be able to get inside the house with ease.

Two years ago, thieves stole a number of Acura cars from a corporation's garage in Atlanta, and, in three cases, they used the GPS units in the cars to find and then burglarize employees' homes.

And just last month, two men were accused of a GPS-guided crime spree in Michigan and northern Ohio. They allegedly broke into vehicles parked at shopping centers, stole the units and then burglarized home after home. Police figure the same pair may have been responsible for burglaries in about 20 communities.

This "take me home" function works in reverse as well, helping police identify the owners of lost or stolen GPS devices. In November, police in New Jersey found a Garmin unit in a small cache of stolen goods. By setting the device to its home setting, they were able to identify the owner and return it.

But the bottom line is that, at least theoretically, some of your personal information could be available to anyone getting a hold of your navigational device.

You may be more likely to be audited by the IRS or contract H1N1 than be a victim of burglars guided by GPS. Yet the risks "aren't negligible" either, said Erhan Kartaltepe, associate director of the Institute for Cyber Security of the University of Texas at San Antonio.

Your home address could join a large mass of information about you that is "out there," available to the public or determined individuals.

Kartaltepe notes that data isn't usually encrypted on consumer GPS devices. So if thieves break the locking combination -- presuming the driver even bothered to lock it in the first place -- they get access to a home address.

Software designers can develop applications to provide extra security for the GPS in iPhones and other advanced cell phones, he said. Many single-purpose GPS devices with proprietary software systems may be unsuited to add-on security apps, however.

Government systems do have encryption, Kartaltepe notes. But it would only become standard on consumer units in the unlikely event of a national GPS data catastrophe involving the loss of millions of pieces of personal information.?Drivers can still reduce the risk with a few simple counter-measures, though.

"We encourage people to use common sense and take the same precautions that they would with any consumer electronics device," said Jessica Myers, a spokeswoman for Olathe, Kan.-based Garmin International.

You can take your GPS unit with you or lock it in the trunk or glove compartment when you leave your car. You can also lock the unit down with an anchoring device.

One company, New York-based Pioneer Lock Corp., has taken its experience with locking devices for desktop computers and has applied it to on-board GPS units. Its StarLock-GPS product hangs onto the unit with a heavy wire cable and a plate glued to it with high-strength adhesive. The lock can be easily released if you want to take the unit with you, said company owner Peter Parsekian.

If the GPS unit itself has a keyboard locking device, Myers recommends that people use it. Garmin has a feature similar to a keyboard lock on a cell phone, she said.  "With the Garmin Lock, you either insert a specific password or drive to a specific location, which you have preset."  At that location, the unit unlocks and its owner can access its data and functions without additional effort.

Still, thieves may find it relatively easy to hack their way into a locked unit over several days.

The best course is to deter the theft in the first place, and the simplest solution is to take your GPS unit with you when you leave your car.

"You wouldn't leave your cell phone or your digital camera on the seat," Myers said. "A lot of times people forget this." Since their GPS is often mounted with a suction cup on the windshield, they almost regard it as a structural part of the vehicle, she said.

"One other thing to remember is to remove the mount when you remove the unit from your windshield," she added. Even if it's empty, it "is a sure sign that there is a device in the vehicle, unless you happened to take it with you."

It's easy for the driver to remove either a dashboard or a windshield mount and place it out of sight. In the case of windshield mounts, the owner should wipe away the telltale smudge left beneath the suction cup.

It's also a good idea not to enter your address into the "home setting." If thieves break into your car while it is parked at work, they may rightly conclude you're not at home. It would be even worse if your car were parked at an airport while you were vacationing in Cancun.

If you have a garage-door opener in your car, you may even want to avoid using another address on your street as your home setting. The thieves could steal the door opener along with the GPS, and then drive up and down your street clicking on the device until a door opened. Instead, use a nearby address on a different street.

The home setting doesn't always point to home. Some drivers input a different address from time to time -- an eventuality sure to confuse any would-be burglars. "I travel a lot and I will often change home to whatever hotel I happen to be at," Myers said "It will get me back to where I want to be, but it's not necessarily my home."

One interesting selection, of course, would be a police station in your neighborhood. That would at least give any burglars some food for thought. But don't count on the police to track your stolen GPS and then retrieve it. Many GPS devices are receivers, not transmitters, and thus don't send out a signal that can be traced.