NYPD has used cell tracking technology 1,000 times since '08
A cell-site simulator, also known as a Stingray, is a suitcase-sized device that can sweep up basic cellphone data from a neighborhood by tricking phones into believing it's a cell tower, allowing it to identify unique subscriber numbers.
Federal law enforcement in September said it would be routinely required to get a search warrant before using the technology — a first effort to create a uniform legal standard for federal authorities.
[...] the policy applies only to federal agencies within the Justice Department and not, as some privacy advocates had hoped, to state and local law enforcement whose use of the equipment has stirred particular concern and scrutiny from local judges.