"So if the cabin crew tell you to "sit back and relax" (yerrccch!) you could be prosecuted if you tried to work, or sat forward in your seat?"
My dear old Dad used to say that you engage your brain before you open your mouth. The same could be said about typing on an Internet forum.
When you read what I wrote and work out what "safety and regularity" mean you will understand why your question is irrelevant as it has already been answered.