Perhaps I was extremely lucky, but back in August I got a Y-> J op-up on HKG-LHR. I'm AA PLT and had purchased a Y fare ticket (does booking in a higher fare bucket help?). When I got to the gate the GA took my Y boarding pass away and fished through a separate stack of boarding passes, and gave me a new one. I was about to complain since I had called a while ahead to get an exit seat, but when I noticed the low row number I kept my mouth shut

I'm flying tomorrow LAX-HKG booked in J. Seatcounter is showing 3 F seats, so I'm keeping my fingers crossed. Even if I don't get it, I'll still have cause to celebrate. I'll finally make it to EXP when I return