There is a lot of this posted all over the place. As for the company Airbnb Inc, I am still not clear what is their security policy and liability regarding door lock codes.
As a customer, I expect that the Company to guarantee that never the same code is given for the same door, to more than one renter. So no previous guest can enter the premises after their rental time expired!
Also the code should be given only on the day the renting period starts, so nobody can enter while other person is still there.
Is any Airbnb qualified representant reading this and can shed some light?