The creativity of the Wanganui gangs protest against gang patch laws was amusing. Like the anti-smacking law we have a nice demonstration here of the ultimate ineffectiveness of laws, because language is not complete.
You can ban gang patches, but it turns out that within a day of the law going into effect it turns out that what Michael Laws really needed to ban was "visual demonstration of affiliation to a gang." Laws (on the statute book) need to be specific if they are not to be a license for police harassment. But when laws are written to address specific behavior, the targeted groups change their behavior.
Was it really the patches that intimidated the residents of Wanganui? Or a group of Maori men gathering in a public place? No one wants to admit they are intimidated by Maori men gathering in public, so instead we get the symbolic politics of banning gang patches.
And what is the line between a smack and a whack? How would you write a law that defined that? A certain amount of pressure, perhaps you could be allowed to swing your open-faced hand at your child at no more than x metres per second. The absurdity is obvious. How would you enforce that with no witnesses and no measurements? Thus, the choice between ruling smacking in or out of the law. There is no way to codify what a "reasonable" smack is. Similarly there's no way to anticipate what will signify gang affiliation, and write a law outlawing it all.
The futility of our language now against future behavior doesn't mean we shouldn't have laws about social behavior, but we should be modest about what they can achieve.