Ooops… please don't jump into some 'conclusions" without knowing the facts.
You are correct: the passenger was not wearing a seatbelt when the accident happened. Why? Because she was at the REST ROOM. Is there a SEAT BELT at the plane Rest Room? Did you find one when you take those planes from Manila to San Francisco and back?
Did not comply with the warning lights? Wrong either. There was NO warning lights when she went to the rest room. (That's according to her affidavit….)
But before anything else… let us wait for the story.