Hell, in Florida it's illegal to cohabitate with the opposite sex unless married! In other words, you can't have a roommate of the opposite sex...you can't live together as a couple (well...unless it's a same-sex thing) unless married either. Sounds crazy, but it's true.
It's one of those outdated laws that no one bothers challenging and no agancy ever enforces...but it's still on the books none-the-less. I remember about two and a half years ago, the guys at a Daytona radio station...what used to be the Crow, WKRO...they called every law enforcement agency they could think of while on the air and basically said, I am living with my girlfriend, will you come arrest me?
No takers
