I have refunded all guests when they have had to cancel due to Covid 19 restrictions/lockdowns. When they request a refund I agree to refund in full. This then tends to trigger a refund of the service charge by Airbnb. Some guests have had to call CS to make sure this happens but so far all the guests have had their service charge back.
I have decided not to change my cancellation policy, I am happy to refund when guests have to cancel due to Covid 19 but by changing my cancellation policy to flexible this would allow guests to cancel their booking for any reason and I cant manage that as a business. In order to make my policy clear all I could do was add my covid cancellation policy to the description part of my listings. This is not ideal and I feel Airbnb need to provide a more flexible cancellation policy to cover what I offer.