My wife travels a good bit and it happened to her again last week. She was seated next to an armrest lifter, i.e. someone so obese that they could not fit inside the armrests.
I would have zero problem telling the guy that the armrest had to be down and if he didn’t fit he would just have to get off the plane. But my wife simply will not say anything because it would “embarrass” the seat thief. And that’s what the airlines are counting on. They refuse to enforce the rules designed to protect the passengers, even though they are aware that most passengers are too shy to make a scene. And of course, once the airplane door is closed, all hope is lost.
It wouldn’t be hard for the airlines to police the armrests to make sure they remain down. Whenever I fly they are able to notice if my seatback is reclined so mucy as a tenth of an inch. If they can manage to force everyone to raise their seats then they can also observe whether the arm rests are down. We need a federal regulation with substantial fines for failure of the airlines to enforce the armrest rule.