Thanks so much @Dave-and-Deb0 for posting. We have tricky regulations where someone bringing undisclosed children could put us over occupancy and threaten our licensing, so this is a very serious issue for hosts and we need AirBNB cooperation. No one wants the headline "8 crammed into one AirBNB room die in fire" to get attention for how this threatens guest safety, and we sometimes need to protect guests from themselves.
I love the suggestions already made.
One tip for hosts: we price our homes for max occupancy, and don't even monkey with "per person" rates. Its a strategy to consider; I don't like systems that reward liars, and by setting a single rate it evens out.
I really love the suggestion of an "over occupancy" charge and a "late checkout" charge--both are related as they significantly add cleaning time and interfere with the next guest's stay. These should be "take the host's word for it" charges, as we've had a terrible time with resolution center staff -- what do we do, take a picture of the guest with a clock in the background? Forward cleaning staff texts saying "guests are still here- I can't get in" with the time stamp?
Our big problem is that with overstaying guests (usually occupancy liars as well) in the peak season, one guest can destroy the time window for cleaning for the next guest, putting hosts in a position where the home isn't clean enough for the next guest, or you need to compensate the next guest because staff needs 2 more hours to get the home clean and ready. There should also be a policy of not allowing overstayers/occupancy liars to leave a review, when that issue has come up. Already, one bad guest generates 2 less-than stellar reviews, because the bad guest is mad that they were caught with extra guests and no leaving on time, and the innocent guest is peeved that the home wasn't clean/ready on time.