Guests occasionally request stays for dates they don't actually want in order to reach me about blocked/reserved dates. When I decline them, my search rank drops about 20 places.
Just today, I had a guest request a reservation for a night that he didn't actually want, hoping I could free up a blocked date for him. I couldn't, so I declined his reservation request, then got an admonishing message from Airbnb to keep my calendar up to date.
Even if I were willing to unblock the night for him, he had zero reviews and only an email verification. That's too flimsy for me.
This seems unfair. My calendar was in fact up to date, and I use "instant book" for guests with two reviews and some verifications. I shouldn't be penalized for declining a guest who tries to work around your booking system, who I can't ultimately accommodate.