Are courts necessary?

Certainly. Wherever laws are made and are to be enforced, there must be some mechanism of determining when and by whom they have been disobeyed, and of inflicting punishment upon those who disobey them. This is the use of a Court and of a Judge. When a citizen claims that another citizen has broken the law, either to his own injury, or to the injury of the public, he may compel that person to appear before a Judge and have it determined by witnesses whether the defendant has broken any laws or not. If it is adjudicated that he has, he is forced to suffer such penalties and punishments as the law directs.