Just had to reply with a real experience I once had on a major UK airline. Passengers on my row (wing exit) were reading papers, and I had a paperback novel. Crew insisted that I must put the paperback into overhead locker for take off, but newspapers were ok. I should point out that no other bags etc.. were involved.
Not only do I personally believe it is nonsense to insist on putting a paperback novel into the overhead lockers, but to then argue that newspapers are ok beggars belief.
I eventually agreed, but the cabin crew member really looked like a numpty.
I suppose everyone can make a 'bad' judgement call, but that is up at the top of my list of silly things cabin crew say.
Why not solve these problems and put all passengers into the overhead lockers, and leave the luggage on the seats?