The mysterious gifts found in the secret knothole of the old oak tree had aroused the kids' curiosity to a near breaking point, so Jem decided to take drastic measures in order to lure Boo out into the open. They decided against Dill's suggestion that they knock on Boo's door and invite him for ice cream. Instead, Jem decided he would try using a fishing pole. The children had seen a loose shutter on the Radley house, and Jem figured he would be able to attach a note to the end of the fishing pole and stick it through the shutter. But before Jem could get the note inside, Atticus caught them in the act. He told them in no uncertain terms to "stop tormenting that man."
In Harper Lee's To Kill a Mockingbird, Jem and Dill, who have been spending a great deal of time together without Scout, come up with a new idea to get Boo to come outside.
In Chapter Five, the two boys decide to leave a note on Boo's porch, inviting him to come out. (They try to deliver it with a fishing pole.) Dill is on the lookout in the front (with a bell to sound the alarm if anyone comes) and Scout is to watch the back—if she wants to be a part of the "project." Atticus does show up, catching them trying to pass the note. When he asks them why they are doing so, they explain that perhaps Boo would want to spend some time with them. (They have no way of knowing how true this is.)
Atticus is displeased that they are "harassing" Boo, and instructs the three children in no uncertain terms that they are to leave Boo alone, and stop any "games" related to the Radley family. Boo, he says, is entitled to his privacy.