In my experience, to help avoid and handle unauthorized guests:
As a host, it is important to provide safety for both guest and your home.
Let the guests know that the space is your home and that guest allowance is to be able to be comfortable with in the space and for safety.
(Good to know: Some city and/or country, it is mandated for guest to announce their visit. You can google this and use this link to communicate with guests. In my case, I was able to find a reliable link and I add this link when communicating to guests. This helps to give guest a peace of mind that you are not here to steal their identity.)
There are 3 places where this can be mentioned for guests to see.
Place # 1: In the House Rules on Airbnb - add in that all guest must provide identification and no additional guests are allowed.
Place #2: Print the House Rules and place it inside the space where guests can easily see it.
Place #3: After booking is confirmed, 3-5 days prior to check-in, remind guest to provide identification documents. If you have the link mentioned above, you may place the link in this communication.