To suggest it might not be paranoid, but merely prudent. To think it's at all more likely that this is a setup against AirBnB and not just... you know, crime... I think is in fact paranoid.
If you want motive, here's one that you might be surprised to learn motivates a lot of crime: the guest needed money for drugs/debt/food/just wanted money, and thought he might get away with it.
Houses get broken into. People get mugged. There doesn't need to be a conspiracy for these things to happen.
Not many opportunistic thieves would pay to rent a target which they haven't cased, right? And meet whoever handed over the keys. Seems pretty bizarre.
If you want motive, here's one that you might be surprised to learn motivates a lot of crime: the guest needed money for drugs/debt/food/just wanted money, and thought he might get away with it.
Houses get broken into. People get mugged. There doesn't need to be a conspiracy for these things to happen.