@Jacob297
if you meet them personally at arrival then no problem. You can send them extra guest charge via Airbnb and make them accept it at your doorstep before you check them in. You are not obligated to let them inside if they show up with extra guests.
If the extra guests arrive afterward then the best would be to confront them and do not leave until they pay for them. If they don't want to then you have to call Airbnb to cancel their stay and escort them out.
Of course, you will not be paid for the rest of their stay.
To avoid it we charge only 10€ for every extra guest, we don't leave extra towels and we don't make any extra beds. If they stay for free at least I will not have any extra work. If I could, I would raise my base price and charge less for extra guests, but I can't.
