Originally Posted by
noFODplease
I wonder why BA stopped offering this - it seems like a decent revenue stream to have ...
Only if you assume that everyone taking advantage of it would never have bought a ticket in the higher cabin to begin with. Otherwise, you cannibalise your ticket revenue and only recoup part of that loss via a cheapie onboard upgrade. (It would have to be a cheapie, because if the upgrade were priced at the sort of numbers that a fare difference would be, almost nobody would be buying one onboard.)
IIRC, it also soaked up too much cabin crew resource at a time in the flight when they are already working very hard and thinly stretched.