Well, if it was my airport, I wouldn't want people sleeping inside. What would the check-in passengers at 0430 think when they arrive to find bodies and blankets (not to mention empty plastic bottles, MacD's stinking boxes, etc) scattered all over the floors and seats. It could also attract undesireables from the town to shelter with their drugs and booze and unwashed bodies. Sorry, but keep the doors locked so the cleaning staff can tidy it all up, and make bigger signs on the entrance doors about the hours open/closed.