It’s not unavoidable. But it’s a black car stopped without lights in the middle of a freeway at night. It’s just a matter of time if no one intervenes (e.g. cops with flashing lights drawing attention).
Ehh. I think it's actually 100% avoidable with a robust self driving solution. One with a smart enough margin of safety would never be in a situation where it has so little information that it initiates a crash on the highway