The etiquette of life is pretty different when you’re in the air, full of rules that do everything from stopping people being jerks to preventing the plane from doing a nosedive. If you’ve half-watched the cabin crew do the safety demonstration enough times, one of these that is probably burned into your brain is a variation on the words “ smoking is not permitted on this flight”. However, this doesn’t always mean that people pay attention to it. While it may seem like an obvious rule that appl…