Bleh! I was on the red eye from Sacramento to JFK, and I found it difficult to sleep.
So, seeing that there was an empty exit row, I moved there, stretched out and went to sleep.
About 2 hours later, 2 flight attendants woke me up and told me that because the exit rows have more room there's a $25 upgrade fee to sit there. They wanted me to either pay them $25 (you can bet there would be NO receipt) or move.
Then they walked away. So, while risking being sent to Gitmo, I stayed in my seat (OK, I had the whole row) and they didn't return and ask for money or threaten me so I suppose it all worked out. They also hustled a woman who was sitting there with her infant, and she moved back to her original seat.
However, they never made any announcements about "upgrading" to that row and frankly they had sold 2 of the rows to a couple of less than 100 pound ballerinas. The emergency exit doors weigh 33 pounds so try to imagine one of those young girls attempting to lift one third of her body weight.
Anyway that incident soured the flight for me.