Anytime I've used the priority line in ANC it has always been met with resistance and confusion. Didn't seem to matter being in F or having SkyPriority with DL, etc. TSA always says something along the lines of "you're not precheck" - true, but this isn't the precheck line. Or "this is for passengers needing assistance" - umm, there's a line for that too on the other side of precheck. This is for priority which I have via (insert credential here). Usually they give in at this point. Lately I haven't bothered with the priority line as the regular lines have been so short.

SEA used to (and I believe still does) have a premium/first class line. Not sure where it is now with the checkpoint remodels / renovation.