@David12693
The Guest responsible for the reservation must go into the reservation section of the platform and adjust the number of total guests. We require this to take place prior to Check-In. The best deterrent in our House Rules states that unauthorized added Guests after the start of the booked period will require a $100 per person, per day payment payable in advance and due at Check-In.
Also, you have to be careful of allowing more guests than the occupancy of the space. Several reasons, mainly safety, but also insurance and any claims that may need to be filed. If AirBnB determines that there were more occupants than allowed or that were not on the original booking reservation, they may deny damage claims.