On Dec 26, 2011, I flew YHZ YYZ MIA.

At checkin in Halifax, the agent said there were a large number of seats available in the J cabin on the A320 from YHZ to MIA and he wait listed me and my travelling companion for an upgrade (I am SE and we had U class fare).

In Toronto, I waited to be called but nothing. I went to the gate agent and asked if she had called the upgrades. She said there were not upgrades waiting for the flight.

I said I was waiting. She said "for this flight"? I said yes, she checked the computer screen and said that J class was full.

Do you think they sold several J class seats that morning? Or did they fill the J class cabin prior to realizing there was an upgrade list?