On a recent trip to Asia, I flew JL ORD-NRT-ORD (which was wonderful), but upon check-in on both side, JL agents initially refused to input my QF frequent flyer number, because "they don't have a partnership with QF".

After arguing for many minutes that I was technically booked on AA and that AA does take QF, and further following extensive conversations among the LH ground crew servicing the flight at ORD for JL, they decided to give it a try, an lo and behold, it worked and printed out my QF number on my JL boarding pass, and a few days later, I checked online and my QF account reflected the proper credit!

If you think this confusion was because the LH people are/were clueless, think again, as I had the same exact (even harder) experience checking in with JL people at NRT. The fact that I was able to show them my boarding pass from the previous flight with my QF number printed on it was only mildly productive. Neither the check in agent nor the supervisor had any clue and both were quite resistant until I persisted and told them to just "give it a try".

I am very surprised because it seemed like I was the first person in history to attempt to use a OW frequent flyer number, other than AA, on an AA codeshare on JL.