AT&T, T-Mobile, and Verizon have all decided to contest the heavy fines imposed on them by the Federal Communications Commission (FCC) for sharing user location information with third-party services without their permission.

The fines stemmed from an accusation that carriers didn't do enough to stop third-party entities from misusing sensitive location data. This was brought to light when Mississippi sheriff Cory Hutcheson used a service called Securus to track people's phones without court orders at least 11 times between 2014 and 2017.

AT&T and Verizon have both filed briefings to explain why they object to the FCC's fine. Both carriers put forward similar arguments, claiming participants in their location-based service (LBS) programs were subject to a rigorous vetting process and were only allowed to disclose rough locations based on cell-tower triangulations after customer consent.

They said that the FCC learned about misuse of Securus's service in 2017, but they only came to know of it after an article was published in The New York Times a year later.

Both carriers decided to wind down their LBS programs shortly after the article was published but the process was gradual to give time to customers to find an alternative solution.