I have seen this type of post before and it seems that Air BNB will uphold the cancellation policy of the host unless the place was booked before March 15th. Presumably if a guest booked during the height of the pandemic, the guest was taking the risk all would be fine. Not a good plan unless you have travel insurance that will pay. Perhaps you could consider offering the guests a credit on future bookings in order to build future business. Just a thought.