I've always wondered if anyone has ever fought those laws and won. This would be a big what if, but say you were in visiting a place that made it not legal to have any means to defend yourself and you were attacked and hurt/killed. Could your family make a court case that if you were able to carry your chosen defense weapon that you could have defended yourself and lived? Sure it would take a lot to proove that but I think it would be possible.
I was reminded of this because I was watching the discover channel last night and they played ads for their show about the people who fought back on the one plane on 9/11. Basically on all the other planes everyone sat still like they have been told, but what if they weren't told to sit still? What if it had been a policy of the airlines to always fight back no matter what, maybe another one or more planes crashing into the towers could have been prevented? It seems quite a libality to prevent people from having any means to defend themselves when its well known that the police can't be everywhere at once.