not sure how it would "accidentally" happen, but there was a post awhile back about someone (IIRC RichardSF) who did a UFC from NC->NF (on intl flight not ps I believe) and the SFO IFL dragons "corrected" the error in a quite unfriendly manner, in addition to denying him entry.

I also once had the dragons deny me entry on a JFK-SFO-SNA itn, claiming I was only entitled to access at JFK, I didn't have a very long layover so it was more principle than anything. For some reason some of the people that work there seem to get joy out of denying people but I also had one of the nicest and very helpful people working there a few years back. So its kinda like jelly bellys, some are OK, some really good and some just make you wonder what they were thinking.

Id also add the KLM lounge in AMS. The new BMI intl lounge in LHR is also close.

In addition, if it wasn't for the crowding the amenities, food and bev in the LH lounges are not too far off from SFO IFL.