I am confused about this as well. When I went into my listing to update after the new policy and features were released, I noticed that the "UNavailable by default" option was automatically applied. Does this mean that all dates are blocked until I go into the calendar and unblock them one by one manually? Or does it mean the opposite... I have to block the dates I want and the rest are open until I say so?
As usual the one thing AirBnB has not done is improvement of the language, user friendliness and communication with their hosts.