Happens to me all the time.
On my most recent flight I was willing to
( even though I previously got down on my knees and swore that I would never) and tried to upgrade my fare from coach to business. I was told, more than once, as late as one day before my flight that business was “full”. Also tried with the gate agents. Got the same story. Of course , when the doors closed I counted at least 6 empty BF seats- three of which the flight attendants drew curtains around to make a sleep corner for themselves. ( they even re-seated someone who was going to sit in one of them) I don’t think that the FA’s are above asking the gate agents to close BF to upgrades so that they can have their “break seats.
You’ve have got to wonder about the airline that says it will be ****ed before it gives a BF seat to someone who paid only $200
( or whatever) but will reserve those same seats for people it pays to fly. ( the FAs). I have got nothing against FAs and know they like to relax on those long flights but I think it is kind of twisted when the airline won’t extend a courtesy freebie to its most loyal when it costs the airline NOTHING to do so.
I am always told that BF is full. I don’t think that I have ever flown a flight where it has actually been full. Maybe its just me.
With CO, its clear- if you want BF seats, buy BF seats