Originally Posted by MSPeconomist

IMO we should forget the stories about the poor running paid FC passenger, probably a 1K, who barely makes the connection after arriving on a late-arriving incoming flight. This is classic GA shenanigans: Upgrade an elite customer but don't tell them about the upgrade and give their FC seat to the GA's buddy, probably a nonrev. The GA assumes that the elite will never notice that the upgrade happened.

However, on some airlines, you can still watch the upgrade list of your seat assignment on a cell phone after boarding; if you notice that you've been upgraded this way, show your device to the FA and move up to your newly assigned seat. Otherwise, make a fuss after the fact when you see that your class flown was upgraded on the FF statement.