Originally Posted by
Top of climb
I don't think this is correct. I know F is never overbooked. I know Y can be overbooked. Not sure about J. And if Y is overbooked and upgrades are required to J, and upgrades are in turn required to F, SQ will do it. A couple of years ago I flew AKL-SIN on the A380; there were six of us originally in F and five op-ups on the day.
It will depend on the situation. If there are few last min paxes willing to pay for the full J price, SQ might open up the seats n upgrade some other paxes to F. (For AKL-SIN, the full J price is actually only slightly lower than the F price). But SQ will usually try not to do so.