It will soon be easy for self-driving cars to hide in plain sight. We shouldn’t let them.

Last month, a video went viral that showed a San Francisco police officer, at night, stopping a car that didn’t have its headlights on. Except that this was no ordinary car. As the cop approaches the vehicle, someone off-camera shouts, “Ain’t nobody in it!” The car, operated by Cruise, a subsidiary of General Motors, is…