New Jersey’s constitution provides its citizens with more protections than the Fourth Amendment when it comes to an expectation of privacy. Today, the Supreme Court of New Jersey issued an opinion in New Jersey v. Earls that creates a new rule of law in New Jersey going forward: except in certain exigent circumstances, law enforcement obtain a warrant based on probable cause to obtain cell location information.
From the opinion:
Instead, our focus belongs on the obvious: cell phones are not meant to serve as tracking devices to locate their owners wherever they may be. People buy cell phones to communicate with others, to use the Internet, and for a growing number of other reasons. But no one buys a cell phone to share detailed information about their whereabouts with the police. That was true in 2006 and is equally true today. Citizens have a legitimate privacy interest in such information. Although individuals may be generally aware that their phones can be tracked, most people do not realize the extent of modern tracking capabilities and reasonably do not expect law enforcement to convert their phones into precise, possibly continuous tracking tools.
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… we conclude that Article I, Paragraph 7 of the New Jersey Constitution protects an individual’s privacy interest in the location of his or her cell phone. Users are reasonably entitled to expect confidentiality in the ever-increasing level of detail that cell phones can reveal about their lives. Because of the nature of the intrusion, and the corresponding, legitimate privacy interest at stake, we hold today that police must obtain a warrant based on a showing of probable cause, or qualify for an exception to the warrant requirement, to obtain tracking information through the use of a cell phone.