I fly a lot so I go get business class upgrades on almost every flight I take. When I fly with my wife I always give her my business seat. Now, obviously, on some longer flights I like to talk to her from time to time.
Now, while you would think there is no harm in walking from Economy to Business and talk to her, I was scolded and “strongly encouraged” to not “come to business class” during the flight.
This not only happened once, but just about every flight!
I have no idea why flight attendants are such “watch dogs” in this regard. Don’t get me wrong, as I fly a lot I talk to many of them, but on this matter never received an answer that made sense.
Same goes for those flights were they ask you to not use the lavatories, even if it is just ahead of you, of the business class. You can’t create a more artificial “separation of classes” than that 🙂
Source: Quora