These YC-but-not-YC rooms fascinate me.
For example, if YC is an enclave within the ship proper, one would be accurate to refer to the duplex suites as exclaves of YC.
Infrequently-used geographical terms aside, I also wonder what controversey might arise if "duplexers" were to permit entry of guests who are not berthed in YC. The duplex rooms are outside the portcullis and curtain walls of YC, (to extend the castle metaphor) so who is there to object?
I could certainly see the missus and myself inviting another couple to our YC duplex for bridge or euchre. However, I'd make sure any proffered refreshments were on my own dime and not, for example, from Top Sail.