The Useless Law in an optional mission that takes place in Pupsville after you have fixed Noble's staff. Before the mission actually starts, if you go and visit Noble, you will see him reading a book with an worried expression his face and he will say, "I never knew such a law existed... Tomorrow, I will tell everyone!" Petasi senses that that was something they were not meant to hear, so he suggests they go and get some rest. Then, the next day both of the exits/entrances to Pupsville will be sealed and Boris will be temporarily out of business. When you go to Noble for an explanation, he will say that he read some books and discovered a law he didn't even know of, which bans all arrivals and departures from Pupsville, for whatever reason. The law is in effect as they speak. He will say he knows how the player feels and he does not approve of the law either, but the law is the law and they must obey.
However, there is a way to get the law removed, but talking to the 3 members of the Committee, Hans, Jeremy and Dorothy and getting their signatures. It is easy to tell where a dog that is in the Committee lives, because they all have leaves somewhere on their house. Dorothy has leaves going around her door, Hans has 2 big groups of leaves on either side of the door, and Jeremy has leaves going around the part where The gutter would be. The 3 dogs happily give their signatures to remove the law and after doing so, all 3 dogs will comment on Noble's behaviour. Dorothy will say that Noble is "such a stiff", Hans says he thinks Noble needs to relax and not take things so seriously and Jeremy says "Gee, that Noble really plays by the books, huh?"
Since the exits are all sealed, this is one of the few missions, and the only optional mission, that forces you to complete it before moving on in the game.