@Patricia2609, I see you don't have too many reviews yet, so I would probably let the extra amount slide this time, because unfortunately if you ask for money before they leave their review, you risk getting a retaliatory negative review - it isn't fair, but that's just the way it is since Airbnb puts us in a difficult position in this regard.
I would book some verbiage in your pre-approval (or post-booking for IB) message asking stating: "Thank you for your request (or booking). I have you down for X people for X nights. Please confirm this is correct, since I need an exact count on the guests per Airbnb policy, so we will know how many beds to prepare for you and per insurance regulations."
This, in addition to setting your rules clearly and expressing them in that message as well as again before they check-in is what I do, and I have never had any issues with extra guests or smoking at my place.