Earlier quoted context omitted.
I wouldn't like it and if I noticed I'd politely ask them to stop. However, (and I'm not a lawyer) I don't think it'd be illegal or even unethical. If someone was recording me napping on a plane I'd treat it the same way as if I was napping under a tree in a national park. It would be a non issue for me. Privacy is something I control by not exposing sensitive information in areas where recording is a possibility. I…
Pretty sure someone could experience serious ramifications if they persisted recording you after being asked to stop. They might even be met by police at the destination and banned for life if they refused the commands from flight attendants after their inevitable involvement.
I'm not sure if they'd be able to extend that to someone recording me although it likely varies by country. I think British law considers continued recording a form of harassment where the same protections don't exist in America.
If I was really really bothered by it for some reason I might raise it once. The cabin crew has the safety of the flight and other responsibilities to be concerned with.