Originally Posted by
intuition
.. or out the door they walk
The confirmed upgrades are the major perk on AY+, mess with that often enough and I can't see the point of re-qualifying.
That is the risk they have to take but I'd imagine that such cases are in reality very, very rare...as when, let's say a 45J A340 goes technical, they usually have nothing available as a substitute so it's either badly delayed, or cancelled.