Uber has a secret, worldwide program called “Greyball” to hide from government employees looking to catch Uber cars operating in violation of local regulations, reports The New York Times.

The Greyball program, which was reportedly approved by Uber’s legal team, remains in use today and is part of a global operation to stop people from, in Uber’s eyes, using its service improperly. That operation is called “violation of terms of service” or VTOS, which addresses everything from competitors looking to disrupt Uber’s operations to law enforcement looking to catch violators of government taxi regulations.

According to the Times, when Uber began operations in a new city where operations weren’t clearly legal, the company would appoint a manager in charge of the Greyball program. That manager could draw a geofence around the offices of regulators, watching for users who might open and close the app frequently — actions that could signify that the user was a city employee tasked with keeping an eye on Uber.

The company would also check user’s credit card information to see if the card was tied to a police credit union, according to the report. Because enforcement officials would buy numerous phones to create multiple Uber accounts for sting operations, Uber would check what cheap cell phones were available in local stores (because city officials did not have sizable budgets) and compare those devices to user accounts.

When a user was “Greyballed,” the Times says, Uber could show a set of fake cars on the app’s map — or no cars at all. The goal was to prevent those users from getting a ride and potentially catching the company violating the law.

According to the article, the tool started as a way to protect drivers from violent opponents like taxi companies and unions in other countries, and Uber told the paper that that remains the primary purpose of the Greyball tool.

“This program denies ride requests to users who are violating our terms of service,” said Uber in a statement emailed to The Verge. “Whether that’s people aiming to physically harm drivers, competitors looking to disrupt our operations, or opponents who collude with officials on secret ‘stings’ meant to entrap drivers.”

It’s no secret that Uber has regularly skirted with taxi regulations around the world, and the company has been completely banned from operating in a number of locales; Austin, Texas is one of the most visible cities in the US to ban both Lyft and Uber.

Ironically, Uber — at least at one point — used similar tactics against its competitors to those Greyball is designed to thwart. The company hired independent contractors with burner phones to request and cancel thousands of rides from Lyft and other competitors to make it more difficult for the other companies to compete.

The Greyball news comes on the heels of a very bad PR month for Uber, including allegations of sexual harassment, a lawsuit from Alphabet’s self-driving car spinoff over stolen technology, and a terribly embarrassing video showing Uber’s CEO being a jerk to one of its drivers. Uber does have a new partnership with American Express, however.