The children put Atticus's advice to good use in Chapter 15, and it is the children's decision to stick by their father against his wishes that saves the life of Tom Robinson. When the children arrived suddenly at the jail, they both recognized that something isn't right. They found Atticus reading a paper under a temporary light in front of the jail just as several carloads of men appeared. When they heard Atticus's dangerous question--

     "Do you really think so?"
... it meant somebody's man would get jumped. This was too good to miss.

When Atticus demanded that the three children leave, Jem wisely stood his ground; and when one of the men tried to manhandle Jem, Scout forgot her promise to stop fighting, and her reflexes took over.

     "Don't you touch him!" I kicked the man swiftly. Barefooted, I was surprised to see him fall back in real pain. I intended to kick his shin, but aimed too high.

As Jem again told Atticus he would not leave, Scout calmly scanned the faces in the crowd until she recognized Mr. Walter Cunningham, the father of her school friend. Scout innocently began a conversation with the man, questioning him about entailments and what a nice boy Walter Jr. was. Scout remembered that Atticus had told her that it was polite

... to talk to people about what they were interested in, not about what you were interested in.

Atticus's advice paid off when Mr. Cunningham eventually "squatted down" and called Scout a "little lady." His own shame overwhelmed him, and Mr. Cunningham decided that the murderous action he and his friends had planned could not be carried out in front of children.