Originally Posted by
cfischer
the rule always existed and is strictly enforced e.g. US domestic; other countries/airlines have a more relaxed approach.
This is what I've found to be the case. I'm an OK Plus Silver holder and I was granted access to a Moscow ST lounge a few years back. I asked (genuinely not knowing the rules on these matters) and they let me in. Lounge staff at other non-US airports have made it clear to me on other occasions that it's not done.