Why do you think there are laws prohibiting the possession of certain items or substances at all? I mean, why should a law abiding citizen owning a bomb, a sample of smallpox virus or a few pounds of heroin be a problem? Crimnals will get them anyhow and if they use them, it`s already illegal. Why is driving while intoxicated illegal? Wouldn’t it be sufficient if only causing an accident while drunk driving would be illegal? That would certainly be way easier and cheaper to police. Why do we have building codes? Unless the house collapses or blows up, nothing bad has happemed yet.