Boo does not leave his home because he feels that people are cruel because of their accusations and discrimination toward him based on the rumor that he stabbed his father with scissors and was locked in the court room's basement. Jem and Scout accept him because they feel that people in this world are cruel based on their experience with a prejudice jury finding Tom Robinson guilty and other experiences. Boo also left Jem and Scout gifts (watch chain, gum, soap sculptures...) and had also saved their lives from Bob Ewell.
Jem's final statement that makes Scout go along with the plan to peek in the Radley window is when he says, "I ain't going back in Finch's Landing 'til I can bring him with me." This implies that Jem is determined to understand Boo Radley and not let fear dictate his actions, which inspires Scout to join him.
Scout cries after realizing that Boo Radley, whom she once feared and misunderstood, had been watching over and protecting her and Jem throughout their trials and tribulations. This reveal of Boo's hidden kindness and selflessness moves Scout to tears as she recognizes the true nature of his character.
Jem makes Scout spit out the gum she found in the knothole of the tree because he thinks it might be poisoned and someone is trying to harm them. He wants to protect Scout from any potential danger.
Jem gets back at Scout by pushing her into a tire.
No, Scout and Jem find two Indian-head pennies in the tree, and they suspect that the person leaving the gifts is Boo Radley, not Cecil Jacobs. Cecil Jacobs is a boy in Scout's class who makes fun of her father, Atticus.
"Mockingbirds" in this story are those people characterized by their innocence which is taken away by exposure to some (unnecessary) evil. Boo Radley most definitely fits this description. Arthur "Boo" Radley is an enigma, purportedly once a bright young boy who, as the result of some past event, had been sequestered away and emotionally damaged by his domaneering father for most of his life. He grew to be a misunderstood recluse - though he never lost his kindness. Indeed, it was his humanity that ultimately brought him back out of the house to help and later save the lives of young Scout and Jem. It is Boo's kindness without prejudice, what me know as "innocence," that makes him a mockingbird. In spite of everything, Boo gives with all his heart, just as Miss Maudie explains to scout that a "Mockingbird sings with all its heart." To injure him, as "to kill a mockingbird," would simply be a sin.
Scout is saved by her ham costume at the end of "To Kill a Mockingbird" when she is attacked by Bob Ewell. The wire in her costume acts as armor that prevents Ewell from causing serious harm, and Boo Radley appears to fight off Ewell, ultimately saving Scout's life.
Scout cries when she makes a connection between Boo Radley's life of isolation and the societal injustice faced by Tom Robinson. She realizes that both Boo and Tom are victims of prejudice and cruelty, which deeply affects her.
Scout feels sad because she realizes that Boo Radley had been watching over them and caring for them from a distance, while they had only seen him as a mysterious and frightening figure. This makes her question her initial assumptions about Boo and feel guilty for misjudging him.
Scout was initially hesitant and apprehensive when she took Boo Radley home, as she had never seen him before. However, she gradually warmed up to him and displayed empathy and kindness towards him, recognizing him as a gentle soul who had been misunderstood by the community.
In "To Kill a Mockingbird," the Boo Radley game that the kids play involves reenacting Boo Radley's life based on rumors and gossip they have heard about him. They imagine scenarios of his life and the mysterious things he may have done, often exaggerating or creating fictional events about him.
Mr. Radley puts cement in the knothole to prevent any further communication or interaction between Boo Radley and the children. This action is driven by his desire to isolate Boo Radley from the outside world.