I think someone's made that reference before, but I don't remember what that means.
The Culture, created by the late
Iain M Banks, are a massively powerful star-spanning empire possessed of god-tier technologies and with AIs (often the minds of planet-sized starships) managing most of the day-to-day affairs of their empire. They are characterised as having a 'post-scarcity' society. Simply put, no-one has to do without anything they want. Their fantastically advanced technology means that almost anything that a citizen wants, they can have, very nearly on demand.
The AIs (who seem to basically run things) can identify and counter a threat to their nation so rapidly that they are basically unbeatable except against a Necron-level civilisation.
The Culture will let its citizens do pretty much whatever they want so long as they cause no harm to each other. Sex with whoever you want or even
whatever you want. Go wherever you want and do whatever you want so long as you don't hurt anyone except in the absolute extreme of self-defence. Indeed this taboo against harming or forcing anything on others is one of the few moral taboos of The Culture's society. 'No', is an absolute and the body and mind of another is their absolute property over which you cannot and must not think you have any claim or control.
I'm sure that it was the use of 'scarcity' that made a lot of readers think that Ardent and his sister are from a Culture-like society and, to a certain degree, I agree. Indeed, it would explain why Ardent didn't think he'd have to pay for anything (or even understand what that really meant) and why he expected people to be generally sexually receptive unless they were busy. Additionally, the fact that Ardent's sister seems to have not directly caused any injuries to anyone in her attack would strongly suggest that she is following something like The Culture's absolute and inviolable 'thou shalt do no harm' taboo.