How did president truman exercise increased presidential powers while in office?

By entering the Korean War without Congressional consent. Rather than making a formal declaration of war, Truman called the U.S. military intervention "police action."

If they avoided arrest that could cause people to dislike them, and they wanted to show how people were treating them and how the police was arresting them for doing nothing. They would be arrested and go to jail and serve their time to show that they are civilized and will accept the punishment even though the punishment is severe and based on racial prejudice.