The Airbnb guys are not dumb, they are well aware of the fault-lines in their model, they know the problems inherent in the accommodation industry, they know that at some point, someone will be beaten or molested or murdered, they know that a host will return home to the horrifying sight of a guest suicide, they know exactly what the media reaction will be, they know exactly what will happen to the notional value of their company, they know that one big compensation order will completely destroy the tenuous math upon which their company is based.