Did you know that Big Brother is in your cell phone? Most people try to keep track of where their cell phones are, without realizing that the phones are actually keeping track of where they are.

Technology is full of surprises, and legal safeguards are often slow to catch up. Most new cell phones now carry Global Position System (GPS) locators, just like the GPS devices used in cars to map a route from point A to point B.

GPS locators in cell phones enable the phone companies to pinpoint precisely where a phone is, with a remarkable accuracy of plus or minus 30 feet. The phone company not only knows which grocery store or hotel you are in at a particular time, but also your exact location within that grocery store or hotel. The phone company knows which restaurants you patronize, which clothing stores you frequent, and how you drive to and from work, assuming you carry your cell phone and keep it turned on during those activities. Which church do you attend, and how often? The phone company knows that too.

Cell phone manufacturers began installing GPS locators supposedly to improve emergency response time to 911 calls. Those calls are rare, of course, but when they occur it is helpful to know exactly where the call originated.

But location can be determined using GPS whether a call is made or not. Simply having the phone turned on is enough for location purposes. Even without a GPS device inside, most cell phones send out signals every seven seconds for the purpose of identifying the strongest signal from a nearby cell tower, and those frequent communications can be used to track its location.

Most people do not fear the phone companies themselves. But the phone companies provide tracking information to the owner of the phone, who may not be the person carrying it, and some phone companies are reportedly even selling this information to private investigators or others. Perhaps worst of all, cell phone companies may turn all this data over to the government.

This issue surfaced in the gubernatorial campaign of Chris Christie, who was the U.S. Attorney in New Jersey for seven years during the Bush Administration. The ACLU complained that Christie was tracking people without their knowledge and without obtaining a warrant by obtaining cell phone locator information from the phone companies.

In United States v. Garcia, 279 Fed. Appx. 616 (7th Cir. 2007), the Seventh Circuit Court of Appeals (Wisconsin, Illinois and Indiana) ruled that there was nothing unconstitutional about the police secretly attaching a GPS locator device to someone's car and then monitoring where that car was driven. The Court rejected an argument that this act violates the Fourth Amendment prohibition against unreasonable searches and seizures.

Near the end of the Bush Administration, its Department of Justice issued an internal recommendation against the tracking of cell phones without a demonstration of probable cause, which is the same requirement needed for obtaining a search warrant. But this issue continues to be unresolved, and it may require a decision by the U.S. Supreme Court to determine whether proof of probable cause is needed before constantly and secretly monitoring someone's location from a cell phone. With the Obama Administration in charge and reports of its targeting conservative groups, some limits on secret monitoring by government may be a good idea.