The setup they describe is so highly specific that it would also fool most human drivers.

Any car company that relies on only 1 type of sensor or only 1 sensor on a car for autonomous driving is a fool. The key terminology is “sensor fusion”, where you have multiple types of sensors to generate an accurate model of the world around the car which is vastly superior to what a human can perceive. LiDAR is only one sensor. Add in cameras and radar which many cars already have and you’ll have a car that can’t be fooled by just mirrors.