Do you think Scout saved her father and Tom the night the lynch mob turned up at the courthouse in "To Kill a Mockingbird"?
Absolutely. This is one of the best scenes in the entire novel. The innocence of a child triumphs over a violent mob.
The beauty in this scene is that Scout runs up to a very dangerous situation, and she has no idea what she is getting into. All she knows is that she sees her father, and they had come to check on him, so she's going to announce her presence.
Stepping into the mob, Scout begins to feel nervous because she doesn't know any of the men. When she notices Mr. Cunningham, she feels better at seeing a familiar face. The irony of the situation is that she speaks to him about his son because it is polite to speak to people about their interests. In doing this, she reminds Mr. Cunningham that Atticus is a father just like himself, and he re-thinks his decision to fight his way through Atticus to get to Tom.
Scout's actions are innocent; she acts only on impulse, and in deference to the good manners she has been taught. When she behaves like this, the men are ashamed of their own actions that night, and they begin to retreat.
If Scout had not shown up, Atticus and Tom may have survived the incident, but there most definitely would have been a confrontation.