I checked in via the internet on CX's Internet Check-in (1000 bonus asiamiles for first time users of this service) last night for today's flight CX 711 to Singapore at 355pm.

I arrived at the airport with one hour to spare, and was told that I was upgraded to Business Class because the flight is full. Woohoo!

While on the airport train transfer , being a busy body that I am, I noticed that the guy next to me was holding a Business Class boarding pass too but he had an economy class ticket. And he wasn't even a MPO - just Asiamiles.

So it's hard to say what on earth goes on in Cathay's computer mind! I would think that it sorts out passengers according to the clas booked, but lately I have seen tour groups being upgraded between Singapore and Bangkok.

If you're GOLD, chances are good that you will be upgraded if economy is oversold. But if it comes down to the 3 Golds and 1 seat left to upgrade, well, I think it will all depend on maybe the class booked in economy class. Y taking precedence, then B, H, M, K and L. But I know I was once not chosen for an upgrade in Sydney and some other non status passenger was given the upgrade ahead of me! So I really can't tell you any secrets.