https://arstechnica.com/tech-policy/2019/05/lawsuits-att-verizon-t-mobile-sp... The four major US wireless carriers are facing proposed class-action lawsuits accusing them of violating federal law by selling their customers' real-time location data to third parties. The complaints seeking class action status and financial damages were filed last week against AT&T, Verizon, T-Mobile, and Sprint in US District Court for the District of Maryland. The four suits, filed on behalf of customers by lawyers from the Z Law firm in Maryland, all begin with text nearly identical to this intro found in the suit against AT&T:

This action arises out of Defendant's collection of geolocation data and the unauthorized dissemination to third-parties of the geolocation data collected from its users' cell phones. AT&T admittedly sells customer geolocation data to third-parties, including but not limited to data aggregators, who in turn, are able to use or resell the geolocation data with little or no oversight by AT&T. This is an action seeking damages for AT&T gross failure to safeguard highly personal and private consumer geolocation data in violation of federal law. [...]

In June 2018, all four major carriers promised to stop selling their mobile customers' location information to third-party data brokers after a security problem leaked the real-time location of US cell phone users. The promises came after revelations that prison phone company Securus offered a service enabling law enforcement officers to locate most American cell phones within seconds. Securus' service relied on data from LocationSmart, a data aggregator that received location information from the carriers. Despite the carriers' promises, a Motherboard investigation found in January 2019 that "T-Mobile, Sprint, and AT&T are [still] selling access to their customers' location data and that data is ending up in the hands of bounty hunters and others not authorized to possess it, letting them track most phones in the country." [...] "The facts don't support this lawsuit, and we will fight it," AT&T told Ars today. "Location-based services like roadside assistance, fraud protection, and medical device alerts have clear and even life-saving benefits. We only share location data with customer consent. We stopped sharing location data with aggregators after reports of misuse." T-Mobile declined to comment on the lawsuit, but the company told Ars that it "terminated all service provider access to location data as of February 8, 2019." Sprint said it is "reviewing the legal filing" but declined to make any other comment. [...] Verizon responded to us, but provided no comment on the lawsuit. The company said only that "Verizon has led the industry in doing the right thing for our customers on these issues."