I know a Delta FA who is often invited for drinks or dinner. She explains she is not allowed to do that, but here is my number, don't tell anybody. She hands them a napkin or a scrap of paper with a number written on it.
When they dial the number, it is answered "Western Pest Control."
Personally, after flying on Korean airlines -- Korean Air and Asiana -- I always get a rude shock when I fly any other airline, especially in regard to flight attendant service.
When I’m flying domestic U.S. airlines, for example, I don’t expect a damn thing. One time I asked for guava juice (it was my first domestic flight after years of flying international with Korean Air) I got a raised eyebrow, a snappy “What do you think this is, a bar?” and a Coke can thrown in my general direction.