Originally Posted by
StayingHomeIsBetter
I have never seen this done starting at the top and descending by fare class, but it is common for them to require a minimum fare class to be eligible (sorry, I don't recall what that fare class was... it's been a long time since I have seen this done).
They didn't do it class by class, but required some minimum fare class, then (when that didn't sell enough) lowered the requirement in 2 or 3 steps to "anybody else in coach".