> If you have an issue with visitors, talk to them. This is externalizing a social cost: Normally your neighbor (that you know personally, ideally, so you can

> If you have an issue with visitors, talk to them. This is externalizing a social cost: Normally your neighbor (that you know personally, ideally, so you can discuss any matters with somebody you know) will take care of their visitors' conduct. When we're away, we sometimes have friends over to house-sit, but we know them, we know their conduct, they know us, and they're not interested in giving us a bad reputation in the neighborhood. With airbnb, the owner of the apartment likely doesn't know their "visitor" (otherwise, why pay a commission to airbnb?) and often they're not around to enforce standards. It's a huge diffusion of responsibility.