Had a very positive experience at Haneda airport earlier this month. Flights were HND - HKG - ZRH on CX PY and ZRH-LCY on BA Y. (separate tickets)

Original staff was a trainee and she seemed flummoxed at my request, but her Japanese supervisor took over once she heard that I was ticketed on 125. They were speaking in Japanese beforehand (which I understand) and the supervisor was saying she doesn't think it was possible. Once she heard my ticket number was 125, she took over and was incredible about it and managed to get around the fiddly BA system which originally wouldn't issue my boarding pass because it was > 24 hours out and I couldn't check in. She issued my boarding passes and gate invitations based on my oneworld emerald number, but after I said I wanted to credit to another FFP, she told me to hang on to my boarding passes for me to use the benefits and also so that I could have priority baggage etc., but she would change it on the backend later. Miles and points posted fine