I just encountered that exact situation in my AP1 car and was asking myself the exact same question. Essentially, the cars that wrecked had been moved to the side of the road, but debris was still in one lane. There was no officer directing traffic, but everyone was just driving into the emergency lane to avoid the debris. Obviously, I had to disengage AP, but my thoughts were the same as yours - there are no programmable rules for this situation. I just followed what everyone else was doing. How will a computer ever know how to make that decision?
The AI for Tesla's FSD is trained every time you disengage...If the cameras can see it, eventually it will learn to avoid it also. I thought there was a Tweet about avoiding potholes also and Musk said it will learn that also at some point. Speed bumps will need to be learned also.