Won't happen.
Here's why;
Let's say you have 30 identical airliners on the ramp. One day one of them crashes....report ,etc, news story, loads of threads on here and at the end of the day Pilot Error. Meanwhile, the other 29 keep on flying, because it's always the pilots' fault, isn't it?
Step forward the future.
30 identical airliners, all drones. One crashes, hmm.
What will the passengers say, oh it's all right, that one was on version9.2.1 and the rest are now on ROS 9.3 so it's ok to fly. Yea, right......
That's what we're there for...sign for it, take the blame for it.