Interesting though -- I've had an opup on 4 of my last 11 flights. Mostly YYZ-BOS so nothing dramatic, but the YYZ-YVR was nice to fly business.

It's rare, but I frankly appreciate it a ton when it happens. In addition the gate agent told me there would be no meal, which was fine but recommended I go and buy something -- went and bought something and ended with a meal nonetheless.

I do think that there should be discretion for the gate agent or the flight attendant to move people up to business class one the flight has closed. I've seen a number of flights take off with unsold or unfilled seats, which seems relatively pointless to me.