One of the issues is that the official punishment for certain crimes does not line up with the punishment the offended party can dole out. Just make most crimes punishable by death and then the post-justice investigation is pretty straightforward - did the individual commit a crime? If yes, then no need to go further as that is the punishment that would have been given had it gone through the court system. Then it's not just the victim that can mete out justice - you see a crime being committed then you can implement the expected penalty. I'm sure there are some crimes for which death is not an appropriate punishment, but as long as you include white collar crimes (stealing money rather than goods is somehow better?) in the deserves death category then all levels of society are subject to the most extreme punishment available. Whether a pack of Juicy Fruit is stolen or you are short-changed $5 dollars - it's all the same.