You must obay the laws of wherever you are.... easy. Get a copy of the laws and keep them handy (in your car/folded up in your wallet) Know the laws, abide by them to the letter, carry the proof. If you are doing as per the law & you are hassled, quote the relevant law, ask for the name/id of the complainant.... and enjoy sueing them
I reckon, false accusation (resulting in false arrest, slander, deformation of charactor & pain and suffering)..... you might end up with a few grand (to buy more guns with of course)
Maybe you should carry a spare tinfoil hat & offer it to the complainant?