Originally Posted by
Vegetable
How does this work in practice though ?
If a flight was full in Y, but had seats in J, and you used your EK Gold status to grab a Y seat - presumably someone (perhaps you) would be op-up'ed to J to make room.
In the same example, if both Y and J were full, I presume they chuck someone off the flight to make room for an EK Gold member using the "Guaranteed Seat" privilege ?

All classes in the flight need to be full to get this benefit as per the T&C. So your example of Y being full and J having space does not qualify..
But this is the only thing clear from the T&C's.. As evident in this thread there are many many unknowns or reasons given from time to time and CS center to center.