Originally Posted by
RatherBeInYOW
If you've encountered this situation (and seen it happen to others) then that is more than my conjecture. I've got into the MLL 3+ hours ahead of time but I'm always on an actual connection, am SE, etc. and I have never been asked for an inbound BP so I don't know for sure and I am guessing.
But I would argue that it is neither in the letter of the rules (this is not a "connection" as far as AC is concerned so subject to the 3h rule, and the domestic MLL would be an arrival lounge not a departure lounge) nor in the spirit of the rules regarding lounge entry.
I think the spirit of the rules are "don't come to the airport stupidly early expecting to use the lounge, but if you fly in and are flying out without leaving the airport, it's fine". So I definitely think it's within the spirit. And you can clear domestic security with an international BP and use the domestic MLL any time, so I also disagree about it being an arrival lounge. I can't count the number of times I've used a domestic MLL with a TB or INT boarding pass.