Today's New York Times has a good and thorough piece on the fight over location information from mobile phones and other unwired devices:
Live Tracking of Mobile Phones Prompts Court Fights on Privacy - New York Times:
In recent years, law enforcement officials have turned to cellular technology as a tool for easily and secretly monitoring the movements of suspects as they occur. But this kind of surveillance - which investigators have been able to conduct with easily obtained court orders - has now come under tougher legal scrutiny.
In the last four months, three federal judges have denied prosecutors the right to get cellphone tracking information from wireless companies without first showing 'probable cause' to believe that a crime has been or is being committed. That is the same standard applied to requests for search warrants.
The rulings, issued by magistrate judges in New York, Texas and Maryland, underscore the growing debate over privacy rights and government surveillance in the digital age.
With mobile phones becoming as prevalent as conventional phones (there are 195 million cellular subscribers in this country), wireless companies are starting to exploit the phones' tracking abilities. For example, companies are marketing services that turn phones into even more precise global positioning devices for driving or allowing parents to track the whereabouts of their children through the handsets.
Not surprisingly, law enforcement agencies want to exploit this technology, too - which means more courts are bound to wrestle with what legal standard applies when government agents ask to conduct such surveillance....