I don't know. It seems like it would be a nightmare to sort through a he-said she-said after the fact when the offended party didn't even book a stay (instead the room was booked by some other person that is insisting "no, it's cool, I know them"), and furthermore didn't even report the apartment not being available when the issue occurred.
It's nice that they were "all cool" with the host and decided to play musical buildings instead of contacting Airbnb right there, but when they did that, they went off the books and severely limited Airbnb's ability to quickly and effectively sort through the issue. A customer that didn't even book a room though the service had an issue and went with a "handshake" from the host to resolve it instead.
Let's walk through the alternate scenario.
Customer desiring a room actually books a room through AirBnB.
Customer arrives and hosts tells them the apartment is no longer available. Customer contacts AirBnB and the issue is dealt with right then and there, and the host is sanctioned properly.
No driving around in a strange city to a place you've never set eyes on, and if you want to book another apartment with the host, you do it on the books.