So it’s come to this: Verizon says it will be adding Surgeon General-style warnings on its phones to make users aware that the carrier will be tracking their location, Forbes reports.

The move comes as a response to inquiries from Congressman Joe Barton and Ed Markey, who were following up on a New York Times article that revealed the dramatic extent smartphones are tracking consumers.

In letters made public by the Congressman today, Verizon, AT&T, T-Mobile and Sprint all admit to tracking user data, but point out that they’re required to do so by federal law, since police rely on that data for investigative purposes.

All of the carriers say they don’t share or sell the location information otherwise. Verizon says that it keeps the user data for seven years, AT&T says between several days and five years, Sprint says for three years, and T-Mobile was unclear about how long it holds the data.

Verizon is the only carrier so far to take any further steps to make users aware of location tracking. I suspect that the other carriers will feel pressured to do so, as it’s an easy way to demonstrate that they care about consumer privacy concerns.