You can't cc on your person at a posted property. However, the way I understood it was that if cc is prohibited and a sign is posted you can leave your secured firearm concealed in your vehicle if the parking lot is open to the public and you are a cc permit holder. A property (parking lot) can be a private property, while still being "open to the public". 69-2441 states "parking area, which is open to the public, used by any location listed in subdivision (1)(a) of this section". It doesn't say that is has to be public property but just "open to the public". In which case a lot of businesses and most business parking lots that deal with customers/services are open to the public, even if it is posted private property. If they found out you had I firearm in your vehicle concealed and secured and didn't like it you still wouldn't be in violation of the law. The most they could do would be to tell you to leave. I wouldn't advise saying "hey I got a gun in my car which is on your property." As long as you leave the firearm secured and concealed in your vehicle your fine.