Mobile devices keep trackin'.

• Author: Greenberg, Pam
• Position: TRENDS

Mobile tracking devices, once the bailiwick of private investigators, spies and law enforcement, are now widely available online and in stores.

The devices can be worn or attached to a car or other object, and the location information they collect can be monitored from afar via computer.

The market for the devices is growing as parents use them to keep tabs on teenagers, caregivers use them to monitor family members or nursing home residents with dementia, and employers use them to manage their workforce.

Tracking devices also have helped in the fight against crime, even in light of a 2012 U.S. Supreme Court ruling--in United States v. Jones--that law enforcement agencies must have a warrant before using a GPS device to track a vehicle.

Of concern to some, however, is that the devices can be used to invade the privacy of others and to commit crimes. Further, neither the Supreme Court nor Congress has addressed whether a warrant is required for law enforcement to access location information, nor have they ruled on businesses or individuals tracking another person's movements.

That's left state legislatures to find their own way. At least 18 have addressed privacy concerns raised when individuals track others without their knowledge. Delaware, Illinois, Michigan, Rhode Island, Tennessee, Texas and Wisconsin prohibit installing a tracking device on a motor vehicle without the owner's consent. Seven other states--California, Hawaii, Louisiana, Minnesota,

New Hampshire, North Carolina and Virginia--more broadly prohibit the use of electronic devices, not just on vehicles, to track the location or movement of a person without consent.

Most of these laws include...