IIRC Boston recently passed an ordinance forbidding landlords to rent a unit to (IIRC) groups of more than 4 unmarried persons living together. The intent was to deal with absentee landlords who rented houses to large groups of students, since (a) the students, as a rule, could outbid working families interested in the same kinds of housing; (b) there have been a number of problems with students being bad neighbors (drunken late-night parties, and so on).

Since Massachusetts has same-sex marriage, I suppose that six Boston College students looking to crowd themselves into a three-bedroom house could take a short trip to City Hall and present themselves to landlords as three married couples....