We had a similar issue last summer season. A guest booked for one person and then tried to bring three more into the studio (STUDIO) apartment. She never entered the property as Airbnb contacted her before her arrival to cancel her based on the false info.
Airbnb allowed her to write a review where she blasted us for being criminal - which Airbnb removed her review while at the same time suspended our listing for 5 days for bad reviews!
We could never get the support team to do anything. 5 days in our only 3-4 month season is a tremendous penalty to pay for something that Airbnb had already deemed was the guest's fault, not ours.