Groups seek to overturn ruling allowing warrantless phone tracking

The Sixth Circuit majority ruled that the police had simply picked up GPS signals that had been "emitted" by Skinner's phone and used it to track his movements. But the civil liberties groups point out that this is an over-simplified description of how the signals were obtained. Cell phones do not routinely emit location data derived from GPS measurements; they do so only when their phone companies remotely activate a phone's tracking capabilities. This fact, the civil liberties groups argue, should subject the tracking to a higher level of scrutiny.