Good summary!

OP- I travel in from the regions generally and on the odd occasion if I have a nice seatmate and get chatting to them in the course of the flight for some reason and learn that they are perhaps planning a trip to GC on their CE/CW ticket if connecting then I would always offer to guest them. You might be surprised at how un-bothered a lot of people are about lounges!

There would, however, be some domestic considerations and I don't think I would ever dare invite any single ladies <40yrs if travelling alone!
Exception to be made if I ever meet PUCCI in real life, of course...