If not, an agent could simply tell me whatever they want?
Don't most people with this benefit simply say , "ok, it's bookable in Revenue on the ac site , it should be available to me as an SE then on points"
Exactly. I went through this several years ago when EVERY fare class was
9, but I could not book IKK and AE/AC claimed the plane was oversold.
Ben later admitted this was an AC IT glitch.
But yes, there could be quite a few seats for sale while a flight is
technically oversold.