You know how they say "ignorance of the law is no excuse"? Have you ever thought about how messed up that is?
First let me preface this with one of my favourite acronyms: IANAL (I Am Not A Lawyer). I don't know the legal theory behind what I'm about to discuss, and my assumptions about the law may be pulled out of my anus. But, as you'll see, that's kinda my point.
In theory, yeah, every good citizen of a city/province/country should know every law. It would be a better city/province/country if the law made sense and every citizen followed it to the letter.
In reality, nobody knows crap about the law. They know that a few things are obviously illegal — murder, say — but that's mostly because they also happen to be wrong. Most people have an inbuilt sense of right and wrong and, failing that, have parents that drill right and wrong into them from an early age.
The law, though? The law doesn't often (perhaps doesn't usually) line up with morality or common sense. And the thing is: nobody is trained in the law except the people enforcing it. There are no classes in school to teach people what is illegal and what is not. The average high school kid can recite the dates of historical events, but the average adult doesn't know which hours they can legally park on a city street.
A kid in grade 3 can do long division, but has no idea that he can get arrested for adding a dildo to a home that already has one (in Arizon, apparently).
If ignorance of the law is really no excuse, then I suppose the expectation is this: at some point in life, outside of school, of their own volition, every citizen of a city/province/country must seek out the laws of the city, province, and country, then memorize every single one.
That's likely impossible. And even if it were possible to memorize every law, it would be impossible to recall that information on cue in every relevant situation. "Hmm, I have this pair of dildos, and I'm travelling to Arizona...let me search my memory of thousands of obscure laws and see if the legal maximum dildo count was 2 or 3."
IANAL, but I am a psychologist, and my expert opinion is that such a feat exceeds the capabilities of the human mind.
That's a pretty damn good excuse.
So we're left with peoples' lives being ruined by other people, based on an expectation of non-ignorance that is literally impossible to live up to.
I don't know what the solution is, or if this is even a problem. We need laws, and generally the system, flawed as it may be, works pretty well. However, this is just one example of many that evokes the horror that many deep-thinking people often feel: the creeping realization that civilization is just a thin veneer of order, relying entirely on lies, illusions, and impossible expectations.