I commend a United Airlines flight attendant for not allowing a self-upgrade to extra-legroom economy class, even if the message could have been conveyed a little more gently.
United Airlines Flight Attendant: No Free Upgrade To Extra-Legroom Economy Class, Even After Takeoff (Yes!)
While flights tend to be more full these days, there are situations where the rear of the economy class cabin is packed full while the front (with extra legroom seats available for an upcharge…