First of all, whether you think it's a "stupid mileage run" is besides the point. UA and SQ should consider it a real trip as long as I bought the ticket with real money.

Secondly, I'm not going to New York. As previously noted, the flight to New York is my return trip after ~12 hours of flying that day. So it's not like I'm looking for a shower at the airport right after leaving my house.

Thirdly, access to the SKL when flying any *A flight is one of the specifically advertised benefits that I pay for as a member of the Red Carpet Club. And access to lounges when flying any *A flight, domestic or international, was the #1 reason why I purchased RCC membership.

I don't see how, especially considering that SFO-JFK is a "premium" route, on which F pax even get FIL access. You give the example of using the SKL on an SFO-LAX flight, which is not what I'm doing. (But I actually don't think it's somehow wrong in that case either.) *G lounge access is routinely permitted on much shorter flights than SFO-JFK, which might even be cheaper...such as LHR-DUB, NRT-ICN, FRA-AMS, etc. But SFO-JFK just happens to be domestic because the USA has more territory than these other countries. So what's the big deal?

The general *G rules do not require international travel--and I suspect that that's because such a rule would disproportionately hurt European and Asian carriers, whose members would often fly UA on domestic flights and be denied access to the RCCs, but whose European and Asian lounges would routinely be used by UA members because almost any flight in those regions happens to cross international borders.

No one should need your permission to use the SKL "once in a while for international flights out of SFO," because *A rules explicitly say that *Gs are entitled to use any *G lounge in SFO every time they fly internationally (and any *G lounge except UA and U when flying domestically"). So why do you only consider it fine if it's limited to "once in a while"?

As noted above, domestic is irrelevant, and mileage run is irrelevant. You seem to think that the lounge is solely for what you want it to be for, but the reality is the opposite. *A rules clearly state that *G lounges are for use by *Gs on all flights, whether international or domestic (excepting UA/US access on domestic itins for UA/US elites--even UA and US are not allowed to exclude other carriers' *Gs on domestic itins!), on any paid ticket (regardless of the member's motive for buying the ticket) or even any free ticket!

A pointless absurdity from the slippery slope. That's nothing like what I'm doing. Especially if you live in SFO and could have showered at home right before heading to the airport. Nor am I telling "every single SFO *G" to shower at the SKL. In fact, I haven't told anyone that they should do it. All I have said was that I was planning to do it...and if other people think it's somehow "wrongful" or "immoral" to use a *G lounge on a domestic itinerary, they will use their own judgment and decide for themselves.

So, I could reply to your absurdity with an equally stupid, opposite one: "How would you like it if a group of passenger vigilantes stood outside the SQ lounge and beat up all the UA *Gs flying in C or Y, whether domestic or international, to keep them out of the SKL and prevent UA from "getting banned from that lounge so fast"? So that SQ lounge access could be preserved for UA *Gs flying F, by preventing the "inflood" of *Gs in C and Y, and keeping the numbers under control. And how would you like it if the vigilantes told every single friend they had in SFO to join them in beating up "lower-class" UA *Gs outside the SKL lounge? It would be such a fantastic way to make sure that SQ doesn't get fed up with the crowding, and that UA doesn't lose too much money paying for the access!!

Hmm..perhaps you want to make an argument from the real world instead?

So what? UA spent money to build a connector for us to use. Why should we pretend that it does not exist? Maybe SQ can make a rule that the SFO SKL is limited to *Gs on international flights (although I'm not sure how they could under *A rules), but until/unless they do that, *Gs on domestic flights are allowed to use the lounge as provided by *A rules. Just because at one point there was no way to get from the domestic terminal to the international terminal without re-clearing security does not mean that, when the architecture changes, *Gs should perpetually live in the past and refuse to use a lounge they have now been given access to.

The point is not "when the lounge was built," but "when *A policy was made," and when the *A lounge access policy was made, there were also plenty of *A lounges that could be accessed by pax flying short flights. That included short international flights, but *A rules specifically avoided requiring international travel, except in the case of UA/US members accessing UA/US's own lounges.

The RCC member rules also specify that SKL access is allowed when traveling on any *A flight. And access to all *G lounges, regardless of the specific carrier or class of service I am flying, or whether I was going domestic or international, was the main reason why I paid for RCC membership.

Do you honestly believe that I am "gaming the system" by using my RCC membership at the SKL, when I paid for the RCC in part because it was specifically advertised as providing access to the SKL and other *A partner lounges when flying on any *A flight? My whole point in buying RCC membership was to get domestic lounge access.

Actually this idea looks really promising given the limited hours of the SKL (although I still maintain that it is 100% proper and reasonable for me to use my RCC membership to access partner lounges).

Can you tell me where to find the $11 shower facility? Is it inside or outside of security? Is it the same security checkpoint that is adjacent to the UA Intl RCC? Do they provide toiletries or should I pack those in my TSA bag?