Not something I've ever seen at the bottom of an apartment posting on craigslist before. I mean, just... why? You... want to make sure no one hears regular sex noises? You don't want your tenants popping out a kid? Taking in a single person guarantees against neither of these. After I posted on facebook, a friend told me that yes, it is illegal, but we're still not going to see the place (an updated 1 br condo in a highly sought-after neighborhood) because who wants to live with a weirdo for a landlord? I didn't think we'd have much success with Mr. Leaf's suggestion of pulling a reverse Spaced.
Just so weird.