Warrantless Tracking

"Outdated laws shouldn't be an excuse for open season on tracking Americans, and owning a smartphone or fitness tracker shouldn’t give the government a blank check to track your movements," Sen. Ron Wyden, a democrat of Oregon, said of the legislation he's co-sponsoring.
Consider cell-site tracking, even via stingrays that simulate cell sites. This type of spying has become an important surveillance tool in the aftermath of the US Supreme Court's 2012 rulingthat the authorities need a warrant to place GPS trackers on vehicles.
The government can often get data on a person's whereabouts via cell tower pings without a probable-cause warrant. And in all the litigated cases on cell-site location tracking, the government argues that cell-site records are not constitutionally protected. Instead, the authorities maintain that the information is a business record that the telcos or other private companies may hand over if the government asserts that reasonable grounds exist to believe the data is relevant to an investigation.
That argument stems from the 1979 Supreme Court precedent that provided the legal justification for the National Security Agency's telephone metadata snooping program that NSA whistleblower Edward Snowden exposed.

What a joke to have a precedent from 1979 being used to determine the legality of tracking American's personal devices without a warrant. Their is absolutely no way to compare the use of landlines in 1979 to tracking an automobiles GPS unit today. It's not even actually using the telco's system to get that location data since GPS data is based on satellites and not cell towers. Not to mention, cell towers are a drastically different form of technology from the switchboards of 1979.