A few yrs ago, out of DEN to LHR with good old Birdseed, the CSD suggested to me that they needed some assistance in cattle. A enormously obese couple (I am talking fatter than lard itself) with a 16 year old kid of Jupitean size (and all of them of obvious nationality) in the aisles, were causing absolute havoc on the "this seat isn't big enough... I got no room.... I got f***ing SFU next to my name....I should be in first... this is a s***hole limey airline" line of talk....both he and his wife was obnoxious to everyone around
The guy was rude beyond comprehension to all around and as he demand his upgrade...
After trying to be charm itself (a hopeless effort), I got rather exasperated and just said "Look, first is for those with a greed for money, not a greed for eating" and went back to the FD, leaving the CSD to upgrade the poor bloke sitting next to them on his own at the end....hehehehe!