@Ute42,
I agree with most of all of your recommendations and comments. Depending upon the space, my regular minimum stay requirement is 2 or 4 days, and maximum reservation length is between 15 and 28 days. I have a strict cancellation policy in St. Lucia, because people were doing exactly as @Erin443 stated regarding making a reservation as a placeholder. In Atlanta, I have a moderate cancellation policy, because most of the bookings are relatively short notice. I do have Instant Book on, a 3 day lead time for bookings, and one of the guest requirements is a host recommendation. If the potential guest doesn't meet those booking requirements, they can contact me to request a reservation, and then I can do my vetting process. I have declined one guy who had a review that stated he smoked weed at the place, and I have a very strict no smoking of anything (including cloves and vaping).
If a guest books far enough in advance, they only have to pay a 50% deposit. Based upon the numbers you mentioned, a guest would be out of pocket $250. This is not small change, but definitely much less than $3500 for the reservation + 15% service fee + occupancy taxes.
Given the significant rise in the number of confirmed coronavirus cases, I suspect that many people are reconsidering their travel plans. Some have health and employment concerns, and they may also be worried that a reversal in re-opening businesses may lead to the unavailability of desired activities.
@Dimitar27, @Ian-And-Anne-Marie0, @Inna22,