Originally Posted by
YEG USER
Who are the operating airlines? If either of the transborder segments are UA, there should be no issue.
Technically speaking I don't even think that's necessary, since you're being transported from the US to TPE, which is perfectly valid for any airline to do.
But again, I wouldn't expect agents to know the rules. In fact, I have ample experience with them overreacting to things that are allowed.
Even if the operating airline made a difference (and I stand by my assertion that it does not), you need the agent to understand that.
So just don't talk to anyone until you're in SFO regardless of what you do, or expect a hassle at check-in. Though best-case scenario would be a rebooking onto ORD-SFO non-stop, which I almost had in BOS once (had it not been for the J0 Y0 inventory of all the flights...)