Years ago on a ship the Captain always signed off the log as he went for rest with the words, "If in any doubt, wake me." I asked why and he said that under maritime law he was responsible for the ship even when asleep and that is the best the company lawyers could come up with to give him a bit of cover.
I do not believe that aviation law has caught up with the concept of commanders rest, so it would be up to the interpretation of the judge on the day of the subsequent enquiry. Live with it.