It's a bit of a game of how you want to ask/tell, and whatever reasons you want to give.
The BA policy with regard to unaccompanied minors made the news, and obviously I have no idea just what was said to the passenger, but if the crew want to move somebody, then they don't really need to supply a reason. The passenger may want to follow it up later, and would be fully entitled to do so, but at the time, it is a perfectly legal request, and so I would expect it to be followed.
This protocol is more widespread than just BA. Whilst some people might take it as an insult to all men, I must admit that I'd rather be seated anywhere else. Not just because I don't want to sit near kids, but because I don't even want the chance of some silly accusation being made. As I said in the earlier post, problems come up with people misbehaving more often than you might imagine, and I've had the police meet the aircraft a couple of times for just this sort of thing.
The light shade is a trivia item, but unfortunately it does come up every now and then. Basically, there is nothing 'illegal' about the cabin crew telling a passenger to close it, and if he doesn't then he is in breach of the rules. Of course, how you handle it from that point shows the difference between good cabin management, and otherwise. Most people are quite reasonable, and something can be sorted out. I guess I'm not cabin crew, 'cos I'd go straight for the military option..firing squad.
I'll toss a couple back at you....business class passenger refuses to put laptop away when asked (on the ground, just prior to doors close); very lightly loaded jet, passenger moves from allocated seat to take an empty trio...once prior to pushback, and again on taxi.
thanks jb. Interesting discussion.
of course the examples I have chosen were specifically designed to show that some requests are not lawful and therefore don't have t be complied with.
I think you are taking a track that as long as a request is not illegal, then it is lawful. I tend to disageee with that statement and would look to any request as needing a basis in law to determine whether it can be actioned or not under the various pieces of legislation and/or crimes acts.
So if a cabin crew, unaware that mothers are allowed to breasfeed wherever they want, decides to ask a passenger to stop it, I think the passenger needs to have the confidence to say 'no' and continue doing it.
The food on board example (for a diabetic) is a bit more difficult, as is the reseating of a male passenger away from a minor.
Asking the diabetic not to eat food is not illegal (anyone can ask someone else to stop eating), but if the diabetic fails to comply, can any charges be brought against them? (assuming, in all these scanarios, that the discussion does not progress ot being intimidating, abusive or disruptive to the crew which is a separate crime).
I don't think a charge could be brought, other than a civil (breach of contract) action.
And breach breach of contract is not covered by the crimes or avaiation legislation. So diabetic says 'sorry, i've got to eat this' - I doubt the crew could have any recourse as they have not issued a lawfully based instruction. Their request is not illegal, but that doesn't mean it is lawful per se.
Same with seating next to a minor. Cabin crew have the right to instruct passengers to move, but as far as I can make out, instructions that passengers MUST comply with (for fear of penalty under the law) must be lawful. I can't find a law that says male passengers cannot sit next to a minor.
What is an airline decided it didn't want black people sitting next to minors? The instruction to ask such a passenger to move would be unlawful (even though just saying the words 'please move' (without giving a reason) is in itself lawful.
As for your examples - all of them clearly concern sdafety related issues. pilots and cabin crew can lawfully issue instructions, which must be coomplied with, if it is in relation to the safety of the aircraft. Not putting the laptop away breaches safety because the cabin crew (a) have to secure the cabin for departure and (b) the timing of that is important as they have other duties they need to perform at certain times... they can't hang around waiting for oe person to stow their l;ap-top.
Moving around the aircraft, to an empty seat is a weight and balance issue, clearly falls within safety (although much easier to understand on an ERJ-45 than on a 747

)
Moving during taxi shows the passenger has failed to comply with lighted placards
and safety related crew member instructions.
So it leaves something like the window shades. Let's say crew member asks passenger to lower shade. Passenger replies 'sorry, I paid for a window seat, i would like to look out'. I agree i couldn't ever see a pilot getting involved in a dispute like this, but let's say she did... pilot comes down and says 'please lower the shade. Passnger (politely) gives the same respose.
What can the passenger be charged with? Have they actusally broken a law? They have failed to comply with a crew member instruction, BUT, was that instruction based on the safety of the aircraft? (clearly yes on take-off and landing) but in midflight? During the day?
It's the same with a police officer issuing an instruction - members of the public only need to comply with instructions that are lawfully given to them. Just because police officers are who they are doesn't mean they all know the law. That's what lawyers are for (and even they get it wrong).
From the breasfeeding example alone it shows that passengers do not need to comply with all instructions. Only ones that are lawful. Whether or not the passenger knows what they are being asked is lawful or not is another matter and i agree these should be best taken up after the flight.
however - would I want to move simply because i was seated next to a minor? I would find that highly offensive and humiliating in front of other passengers.