If you think the police shouldn't be allowed to track you without a warrant, why do you think it's okay for private companies to do it?

The Supreme Court heard arguments from the Justice Department last week defending the unchecked use of GPS devices planted on suspects' vehicles to track and record their movements. It stems from a 2005 case in which police in Washington, D.C., secretly attached a GPS device to a suspected drug dealer's vehicle.

The device helped police trace the man to various locations, where they in turn found drugs and money. The man's conviction was overturned on appeal based on the idea that officers must obtain a warrant before attaching such a device to someone's car.

The Supreme Court judges seemed flabbergasted when deputy solicitor general Michael Dreeben told them the police -- indeed a variety of government agencies -- could monitor the justices with a GPS anytime, anywhere without a warrant. Big brother, 1984, invasion of privacy -- the judges brought up all these issues; a verdict isn't expected until the spring.

Such monitoring is akin to eavesdropping using a wiretap, which requires a warrant. That's because unlike most GPS navigation devices, these police-controlled GPS units can be two-way communications devices that use the cellular data network to continually send back information on the vehicle's location to the police. Essentially, the police bugged the suspect's car.

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And if you think it's wrong for the government to track you in this fashion, then why do you think it's fine for countless corporations and marketers to track you even more closely, following you on vacation, recording what you buy, when you go to your child's school, when you walk through the park, when you go to the doctor's office?

That's exactly what your smartphone does, after all.

Smartphone apps commonly track your location and how you use the software, and then transmit the information back to their headquarters. Google follows and records all your searches. Facebook follows all your moves not only on its site but on countless other connected Web sites. Verizon Wireless recently changed its privacy policy so that the company can track a customer's location, Web browsing history, and apps -- and then sell that information to other companies.

It all makes the (secret) police GPS devices seem harmless by comparison. So why do we accept it?

Advertisers and many technology companies point out that we as consumers accept it in order to get something else of value: a free app, information about what's nearby, directions to a gas station, the ability to share party photos and political opinions with friends gratis.

But the problems with this unregulated and unchecked practice are legion, privacy advocates say. Children are tracked. Medical records can be compromised. Potential employees can be turned down for work based on false information collected about them without their knowledge through these sites. The list is nearly endless.

And the companies collecting this information on you have little control over it.

Klout, a site that attempts to track social media use about individuals and then give the person a power ranking, recently was caught collecting data on children. It has since changed its software to eliminate the problem, but as we all know, kids are on plenty of social networking sites that track them, whether they are supposed to be there or not.

Even a GPS navigation company that was innocently collecting anonymous and useful traffic data ran into problems when a municipal police department used the information to set up hidden, stationary speed traps. In effect, the people offering the information on traffic conditions ended up being penalized for opting in.

In the case of the police monitoring a suspect's movements, authorities argue that monitoring served a utilitarian good: It put bad guys behind bars. But bad guys can jam a GPS tracker with a $50 gadget.

Other law enforcement advocates argue the GPS bugs save money and manpower in a tough economy. Then why not allow police to forego warrants entirely, critics argue? That would save time and money, too, they say.

There's something about the car and any perceived violation of it that really gets people upset. OnStar discovered this when it tried to change its terms of service to potentially let it sell personal tracking information to other companies unless a customer expressly forbade it. A hue and cry ensued, and OnStar changed its mind.

Perhaps we're all still enamored with the romantic American ideal of the freedom of the open road. Too bad we don't feel that way yet about all the technology we use.

Follow John R. Quain on Twitter @jqontech or find more tech coverage at J-Q.com.