Driverless Waymo cars in California unexpectedly stopped on their own this week and immediately flagged teenage riders to police.
FOX 11 in Los Angeles said the cars detected illegal activity and hit the brakes.
The move triggered new questions from privacy groups about how Waymo handles what cameras inside capture.
NPR aired parallel concerns over constant passenger monitoring in Waymo rides.
Reason Magazine noted that anyone breaking the law inside Waymo vehicles should anticipate cameras to keep detailed records under any circumstance.
The incidents come as Waymo grows its service area and encounters more pricing reviews.