They ruled that cops do need a warrant to track you via your cell phone:

Over 40 years ago, the Supreme Court outlined what has come to be known as the “third-party doctrine” – the idea that the Fourth Amendment does not protect records or information that someone voluntarily shares with someone or something else. Today the Supreme Court ruled that, despite this doctrine, police will generally need to get a warrant to obtain cell-site location information, a record of the cell towers (or other sites) with which a cellphone connected. In an opinion by Chief Justice John Roberts, the five-justice majority pointed to “seismic shifts in digital technology,” which have allowed wireless carriers to collect “deeply revealing” information about cellphone owners that should be protected by the Constitution. Roberts characterized the ruling as a narrow one; indeed, the majority at least left open the prospect that police might not need a warrant to get information about where someone was on the day that a crime was committed. But the decision still drew sharp criticism from the dissenting justices, who complained that it is likely to imperil, in the words of Justice Samuel Alito, “many legitimate and valuable investigative practices on which law enforcement has rightfully come to rely.”

Justice Alito, just because law enforcement likes being sloppy and lazy does not justify continual and meticulous invasion of privacy.

The name for a society that allows police to act that way is a police state.