Scout, Dill, and Jem watch the trial from the balcony so that we can see the trial from the black community's perspective too.
During the trial of Tom Robinson, all of Maycomb seems to come out. The trial is big news. As a result, the courtroom is packed. In addition, Scout and Jem are not really supposed to be there. They wouldn’t miss it for the world, but they don’t want their father to see them. So the balcony, high above the courtroom, is both the only seat left and the ideal place to watch.
On the way into the courtroom, Scout gets separated from the others by the gaggle of onlookers.
We knew there was a crowd, but we had not bargained for the multitudes in the first-floor hallway. I got separated from Jem and Dill … (Ch. 16)
Due to this delay, by the time they got into the courtroom, there were no seats left. The trial was a combination of entertainment and required viewing for Maycomb, whether you were man, woman, or child. A black man was accused of raping a white woman. It was big news.
The children also overhear conversations about Atticus, and whether or not he is a traitor for defending Tom Robinson or should get a pass for being forced to do it. This is a continuing theme in the book. Some people feel that what Atticus is doing is not right, and others feel he is just doing his job. The few who feel, as Atticus does, that a black man deserves justice, seem to be keeping quiet.
Reverend Sykes, upon seeing that there are no seats, offers the children a seat in the balcony with the black community. They have been relegated to the balcony due to discrimination—separate and not equal. Of course, the seats are high above the courtroom, not “front row” seats, and not good seats. The advantage though, is that we get to see the perspective of the black community.
Reverend Sykes came puffing behind us, and steered us gently through the black people in the balcony. Four Negroes rose and gave us their front-row seats. (Ch. 16)
When the members of the black community give up their seats, it is not just the obligatory and customary respect given of blacks to whites. It is also respect for who the children are specifically. The black community admires Atticus Finch because they know him to be an admirable and fair man. He is defending Tom Robinson, and actually defending him. You can see this at the end of the trial, in one of the most famous lines of the book.
All around us and in the balcony on the opposite wall, the Negroes were getting to their feet. Reverend Sykes's voice was as distant as Judge Taylor's: "Miss Jean Louise, stand up. Your father's passin'." (Ch. 21)
This is a gesture of respect for Atticus Finch as the trial ends. He makes sure that his children show him respect too. Even if Atticus does not win the trial, the members of the black community till respect him. Even members of the white Maycomb community respect him, as seen in Mr. Underwood’s scathing editorial against Tom Robinson’s death. Atticus Finch showed Maycomb the error of racism’s ways, even if he did not get an acquittal. He was able to shake it loose a little.