@Huma0, interesting topic to bring up.
I can tell you that of the 17 guests I have had, I only had issues with 2- the same issue. These girls (not the same booking) were 21 and 29 years of age. Both had plans to meet up with boyfriends who also happened to be in town, never mentioned this, and both brought those boyfriends back to their room in the middle of the night. When I told them the following morning that this was definitely not acceptable, one looked crestfallen and asked if he could please stay as well, the other apologized with the lame excuse "Oh you know how these things just happen, love and all", then said she'd like him to stay with her and offered to pay more.
A lot of young people these days seem to be entirely self-absorbed and have an attitude of entitlement. They have grown up in the age of fast communication, instant gratification, "branding", endless selfies, and reality TV, which gives the impression that everyone can be a star, regardless whether they have any talent or particular skill outside of self-promotion.
I property manage a small house in my town, which is rented out on long-term lease, as opposed to vacation rental, in addition to my own in-home hosting. At one point this house came up for rent, and I offered it first to my 35 year old daughter, who was looking for a place. One of the first questions she asked was- "So will it be alright if I list it on airbnb for the weekends and go sleep on a friend's couch?" I was pretty shocked, said, "Of course not, it's not your house". She got offended, questioning me as to why, and implying that I was being unreasonable (the owners only want long-term responsible tenants) and denying her a right she felt she was entitled to.
I can assure you I didn't raise her to think like this and her 2 older sisters would never act so entitled.
Think of the marketing words these days- Iphone, Ipad, Ishop, "personal size" bar of soap. These product names and descriptions are designed to play into a "me" culture and appeal to one's sense of personal importance.
I have no idea what the solution to this is, except to try to explain to these young folks when the opportunity arises, why "me first" does not make for a well-functioning society.