Robotaxis fans praise the privacy and intimacy that a driverless car offers. But don’t forget: Waymo could be watching.

The case has been made clear again and again, most recently in San Mateo after Waymo reported two 15-year-old passengers to the local police department.

Jeanine Luna, a spokesperson for the San Mateo Police Department, told Business Insider that a Waymo representative called Monday afternoon after the company believed two passengers were “handling a firearm” and may be intoxicated.

The Waymo representative told police they could see inside the vehicle and described a black object passing between passengers. At one point, the Waymo representative reported seeing what appeared to be a “rollback,” Luna said.

Waymo did not alert passengers that it had contacted police, Luna said. Passengers were “told the vehicle was having trouble” and that the Waymo was being stopped in a parking lot.

“The doors were never locked and the occupants were able to exit the vehicle before police arrived,” Luna said, adding that the representative continued to provide police with live updates.

In a social media post, authorities said they determined the firearm was an “Orbeez” gun, which fires gel beads, and that the passengers had been drinking alcohol. No injuries or property damage were reported.

Investigators have requested the cockpit video from Waymo and are awaiting receipt, Luna said.

Waymo declined to comment and directed Business Insider to its public guidance on in-car cameras and microphones.

The camera is always on.

Waymo robotaxis are equipped with cameras and microphones outside and inside the cars. The company said in public material that the cockpit cameras are “on and recording.” The microphones are activated only during a call with the passenger mount or if a passenger decides to turn them on.

Waymo said it uses the cameras to check cleanliness, locate lost items, help during emergencies, enforce in-car rules and promote safety. Their support team can also review recorded videos after an issue is reported and, “in more urgent circumstances,” access live video of the ride.

As Waymo increases ridership, multiple cases have shown exactly how the company uses its in-cabin system to flag behavior that could violate Waymo’s terms of service.

Last December, when a woman gave birth in a Waymo while traveling to a San Francisco hospital, the company said one of its remote support agents detected “unusual activity,” prompting them to connect with passengers and then call 911.

More recently, Waymo has been trying to curb underage vehicle use, as some state laws prohibit those under 18 from riding alone.

Waymo told California regulators that it uses indoor camera checks to flag potential violations and that it can’t always reliably determine the age of “older teenagers.”

This crackdown has led to some false positives, in which an adult passenger has been mistaken for a minor.

The cameras in the cabin are only part of the detection system. The company has said it also uses machine learning to help identify potentially incapacitated passengers, as well as smoking and seat belt violations that could prompt a human review of cockpit information. The company said it does not use facial recognition or any other biometric identification technology.

Waymo has not publicly disclosed the full range of behaviors its systems can recognize or exactly what prompts an employee to access a live stream.

The company said it may share data with authorities to comply with legal requirements, enforce its agreements or protect people’s safety. Waymo previously told Business Insider that data requests generally require a court order when police seek data, and that it will challenge requests that lack a valid basis or are overly broad.

Waymo’s growing ubiquity (and the perceived privacy it offers) has created unique user stories.

Employees have used it as an office on wheels, while some more playful passengers have used the space to have sex inside the robotaxi.

Riders, you have the back seat to yourself. It’s just not always necessarily private.