Honestly, there are no such 'ettiquette' or 'manners' necessary or expected in raising the screens. They want to raise it, they raise it. Whatever timing that happens to be, doesn't need to be confirmed with anyone else unless it is a safety hazard, and if so, there will be rules and they will be locked by the crew. If it wasn't, then there shouldn't be any problems. There shouldn't be any expectations nor ettiquette requiring anyone to socialise with anyone else, including a "hi". They ahd no obligations to say hi to you nor would it prevent crew from doing their jobs.