Do not break your own rules unless you are ready for the consequences. I see a pattern/similarities in many posts here regarding difficult guests/guests who break house rules. Yes, they do exist. From about 4 years of hosting, I have met many different kind of people/guests, including the difficult one. However, there are people who are just difficult, and there are people who are being difficult because they see the opportunity for them to do that.
One of the common issue that I see in the forum with difficult guest started with "reservation for 2 (and your listing is only for 2 people), but 4 people show up. I feel bad/it was late at night, so I let them stay" or "they asked if their friend can come visit (even though your rules say that no visitor is allowed), I feel bad/I am afraid of bad review, so I let them do that" then instead of 1 friend, there are 4/5/6 friends show up. That is what I meant by breaking your own rules. If the listing say 2, then do not take more than 2. If the listing say no visitor, then do not take any visitor. UNLESS you are ready for any consequences it causes. When you break your own rules, it makes it look like you are not taking it seriously/honoring it. Then guests might think, why should they? They get away with "breaking" one (per your permission), so they might wonder what else they can get away with. Do not put yourself in that situation, it is like a snowball that will get bigger and bigger... yes, there are people who do not understand boundaries and will push you to your limit. When you break your own rules, it will be harder to enforce the rules because you (the one who makes the rules) break it too.