I'm very well aware of the common law. In fact, I'll give you a real-life example that happened 20 years ago. At that time, I actually was a legal aid lawyer. A person was charged with shoplifting a 2ยข screw from a store. The person was a 75-year old veteran who had never been involved in criminal law. This individual at that time had purchased something like $600 worth of goods, but he was charged because the institution had a pro-charge policy that any shoplifters had to be prosecuted, regardless of the amount.
That person was acquitted on that principle, but it should not have got to that point, quite frankly.