No resemblance to persons living or dead? Think again.
Stranger Than Fiction featured an author who was unknowingly writing about a real person. While Emma Thompson's work seemed connected to Will Ferrell's life. But what happens when you're not in that movie and you write a book, thinking that the characters are fictional and have no intentional resemblance to persons living or dead... and guess what? Someone does have your character's name and they're real enough to sue you for libel.