Using technology from Path Intelligence, major malls and retailers are gathering "survey data" on shoppers' movements by using their cell phone signals as "cookies" to follow them through their retail adventures.
The technology, from Portsmouth, England based Path Intelligence, is called Footpath.
"While Footpath uses only the signal fingerprint of the phone, it does give a fairly accurate record of where the phone has travelled through a mall."
"There's just one problem with this type of detailed tracking: it's technically illegal, according to Mark Rasch, the director of cybersecurity at CSC. Thanks to court interpretations of provisions in the USA PATRIOT Act, he said in a recent blog, devices that measure cell phones' signal strength could be considered to be "pen registers"—monitoring devices that require a warrant."