Like Ange, I think Airbnb gives back deposits too easily. A guest booked two months before the due day. Came three hours early, claimed my 'apartment' (it's a four story house!) was empty, took a motel for the whole three weeks (or so he says) and then e-mailed me to say he thought he had the right house. Airbnb refunded all his money. The guy was lying through his teeth.
Also I have had several people booking for weeks but only for Mondays to Thursdays each week. Why require a review each time they 'leave'?