From my own experience bnb does not block security amount on a guest's card so only if the guest confirms the requested payment for damage you will get your money. Bnb will keep sending you emails tbough that they are trying to reach guests with no success. So effectively this system does not work.
I am going through the process. Tenants destroyed a brand new penthouse in Berlin and Airbnb is no where to be found. I am not able to rent the apartment again and as the apartment was brand new, I sent the invoices of all that I had to repay and need to replace but more than a week has gone by and nothing. Its pretty clear Airbnb its not prepared to solve problems.