I was a deb in South Carolina. Our club rules specify that guests at the ball MUST be in tuxes and floor length gowns or they will not be allowed in. I can't speak for all Carolina balls, but I think you should stick with floor length to be safe. You don't want to be turned away or even worse, if you did get in everyone would tell you how cute you looked and then whisper about you behind your back. Just kidding. Well, not really.
