Guest Attire For Northeast Wedding

Is it a faux pas to have a Friday night wedding in NY/NJ and NOT require guests to wear formals? The reason I ask is because I`m from the South where very few weddings require guests to wear formal wear. I want my friends and family from the South to feel comfortable at the wedding. Plus, I don`t want anyone to feel that they have to rent a tux or buy a formal gown in order to attend the wedding.