That kind of “metadata” can be incredibly valuable, as law enforcement agencies discovered long before the rest of us. The cellphones we carry everywhere establish a clear log of our daily travels and can go a long way in telling the story of our lives.The law doesn't just cover cell phone metadata, but requires that law enforcement get a probable-cause warrant for tracking a suspect in a criminal investigation by social networking check-ins, or via a GPS tracking device. A few states have the warrant requirement for GPS tracking, but Montana's is much broader. A location privacy bill passed Maine's legislature last week, and is waiting action from the governor. The Massachusetts legislature is expected to take up similar legilslation. Last year, California's Gov. Jerry Brown vetoed a bill requiring warrants for location tracking, arguing it stymied law enforcement.
In recognition of that fact, the Montana Legislature this spring passed a location information privacy bill, which requires a search warrant for location information recorded by an “electronic device.” There are exceptions to the warrant requirement, including when the cellphone is reported stolen or to respond to a cellphone user’s emergency call.
Steve Bullock, the governor of Montana, signed it into law on May 6. The American Civil Liberties Union, which tracks cellphone tracking laws across the country, called it the first such state legislation.
Montana could be leading the way for other states, being the first to enact it. It might even provide some momentum to federal legislation.