Some places have unusual mandated laws. This is why tourists must acquaint themselves with it before immersing themselves in whatever the place has to offer.
Laws are created for the common good. It passes on different stages before it becomes a law that everyone must follow. If you commit something against the laws, you'll be fined or even go to prison. These are laws that are too crazy to be considered legal.
There are rules that a visitor from another country might find doubtful or even funny but here is a list of weird laws that are being implemented in the United Kingdom.
With changing laws regarding possession of marijuana in Colorado and Washington in effect, airports are figuring out ways to dissuade passengers from taking their goods on board, while passengers are figuring out the regulations which can vary from airport to airport.