Police in San Mateo, Calif., posted Monday on social media that they had apprehended a pair of teenagers from a Waymo driverless robotaxi after the company alerted authorities to suspected criminal activity. It's the latest incident involving video surveillance of passengers and others by autonomous vehicles — raising questions about the limits of privacy in such vehicles.

  The Facebook post by the San Mateo County Police said: "Parents do you know where your teens are? @waymo does!"

  The 15-year-olds were allegedly drinking alcohol and shooting toy guns from the car, according to the police. They said Waymo's systems detected behavior that then triggered a safety response, after which the company disabled the vehicle and contacted police.