My understanding is that they don't publish exact information in marketing materials due to contractual requirements with some of their partners. I don't think it is an attempt to be shifty in their sales presentation. If you call them, they will provide you with more details.

I love Priority Pass. It is not as good as joining the Red Carpet Club in that you do not receive access to the hub locations (except SFO's international location). It is better in that you receive access to many more lounges.

In the UAL hub cities, there are some viable alternatives. LAX has the Continental Presidents Club in T6 (convenient to some of the UA gates), ORD has the Northwest WorldClub/Continental Presidents Club near the UA Express gates, SFO is a bit of a walk to the Delta Crown Room Club, WorldClub, and Presidents Club (outside of security), DEN requires a ride on the tram to access the Presidents Club (near some UA gates) or the Crown Room Club. As for IAD, I haven't been there in ages. I can't recall if the WorldClub is accessible from the UA gates or not.

Priority Pass generally gives you access to:
- all America West Clubs
- Aero Mexico Salon Premiere
- all Air Canada Maple Leaf Lounges (inside Canada)
- all Continental Presidents Clubs
- all non-hub Delta Crown Room Clubs (plus the international concourse ATL location)
- all Northwest World Clubs (inside the U.S.)
- all non-hub United Red Carpet Clubs (plus the SFO international location) (not including unstaffed locations like CLE)
- many US Airways Clubs
- a plethora of other lounges across the globe