Whereas a conversation with your prospective roommates might have resulted in them agreeing that nobody wanted the cupboard under the stairs, so they could prec

Whereas a conversation with your prospective roommates might have resulted in them agreeing that nobody wanted the cupboard under the stairs, so they could precommit to allowing your $15 rent and making their bids sum to $85 for three rooms. The problem with game-theorist economists is that they always neglect long-term externalities because they're messy. Having a reputation as a decent human being is a long-term externality that's very messy.