FWIW, AS wouldn't book me LAX-SEA/PDX-SFO so I could catch CX out of SFO... They only offered LAX-SJC and said I have to figure out how to get to SFO on my own, which is too much of a headache...
However, I am curious about their routing rules for JNB redemptions
All in all, I got LAX-YVR-HKG-JNB-HKG-JFK, so it is all good