I was thinking about this myself! My car has ACC, and sometimes I’ll be using it in traffic with it matching the speed of the car ahead while leaving a safe distance but some dotard will be tailgating me and flashing his lights trying to force me to close up the gap for zero benefit because there’s another 10 cars ahead of me. I don’t need to touch my pedals so I don’t. If it had lights indicating that the car is driving itself then they might be inspired to be less aggressive.