If the law says you may not go around in your birthday suit in public, you go to prison for breaking the law. If you feel the principle is so important, you could lobby for a change in the law, but you may not just defy it.
I personally would be much offended to be confronted by a naked man in any public circumstances, and I am quite sure so many other people would be affronted that the law will not be changed. He will just have to lump it.
There are plenty of laws I don't like, but I don't break them "on principle" ( not "principal", by the way )