It's not like law was ever going to fit onto a note card, unless the law was "What King George says, goes". Even if you assume no interference from organizations manipulating the law, life is complex and sometimes morally ambiguous. Even simple board games have rule books of many pages- or, those that don't, frequently leave the players wondering about some ambiguous circumstance.

Remember, too, that our legal system was designed to temper the "everything is probably illegal by some interpretation..." nature. That's why you have a right to confront your accuser, a right to a jury of your peers, the "reasonable man" standard, so on and so forth.