I've had terrible experiences while travelling extensively and staying semi-permanently where landlords do anything they can to keep your deposit, especially when you don't speak the language so well. I'd not be comfortable having a stranger be able to claim I made some kind of damage, and it become some kind of paypal-like black-hole of unwarranted claims. Ultimately reading this, I feel so sorry for the host, as a random, rare victim of a dehumanizing crime. It could have happened on craigslist, or via a friend-of-a-friend. Not to say that AirBnB doesn't need to address this, but holding a large amount in escrow like a car rental deposit would be offputting to me (with car rentals there is clear evidence, and you do a full inspection beforehand, though I'm sure it's possible to get burned on this).