I noticed the paperwork for my Sixt rental out of ATL stated that you could only drive into Florida or Alabama, and there were stringent conditions attached, Stating I needed to have a return flight out of ATL to be able to leave the state at all. This is a problem for me as I usually book my flights at the last minute since my schedule is unpredictable.
I often need to go into SC to visit clients so this is an issue for me.