On the A340s AC used to use the mini-J cabin for upgraders and everyone knew you were different and could be shunned at all costs. Often, upgraders had to have stamps put onto their foreheads too for easier identification. And they got the left-over economy meals, not the full J menu. Even economy passengers knew you were like a leper! And I am sure the FAs watered down the booze and took the mouthwash bottles out of the amenity kits...