Originally Posted by
jon503
It really seems that YMMV on this one. Every single op-up I've gotten happened at check-in. Those were all oversold economy flights btw and it's only happened a handful of times in over 6 years (for reference, I'm regular D). That said, I didn't fly that much intra-Asia in the past, but have done more so lately and the frequency of op-ups has increased a lot. This matches what I've read on this forum in the past.
There really is no noticeable pattern for op-ups. The only reliable likely factor is oversold Y, but I've been upgraded without oversold Y cabins before.
Short-haul/inter-asia flights: I get an op-up around 70-80% of the time. The Y cabin on a lot of these flights have not been full.
Long-haul: very rarely, although period of travel significantly boosts your chances. For example, this past Christmas/new year's period, I was flying Y on SYD-ICN. That time of the year is notoriously busy, and on both legs, I was upgraded to C. At check-in on the SYD-ICN leg, and at the gate on the ICN-SYD leg. Prior to that, I haven't scored that many long-haul op-ups, although I did have a memorable SYD-ICN-JFK trip where I was op-upped 3 out of 4 legs (
Op-ups still happen... ).