To make matters even less intuitive, if I was Gold on some other airline than UA/US, such as Aegean, all of sudden I would have access to UA/US Clubs when flying domestically in the US (as per the rules above). So members of their own mileage programs are at a disadvantage!?
So you're saying it's a rule implemented on a lounge specific basis? Would that be available online somewhere, or you have to call them/show up and see what they say?
You realize how crowded the lounges would be if all domestic golds were admitted?