My question is slightly off topic from OP's discussion, yet still relevant, so I would ask it in this thread.
I have this itinerary booked in Y:
SFO-YVR UA
YVR-NRT AC
NRT-PEK CA
All are connecting flights with 3-hour layover.
AC is apparently the MSC and UA allows two free bags to Japan. Will UA charge $70 for a second check-in bag b/c the final destination is in China?