I experienced this first hand at my sis's HS graduation in a different IL public city school a week ago. A certain ethnicity felt it appropriate to yell names THROUGHOUT the ceremony, even during the valedictorians speech. They would shout across the arena calling each other's names. Not the students, mind you, but relatives in the audience. After the speech, the head of ceremonies made a statement about curtailing the senseless yelling. Even with this, they still occasionally yelled. Quite aggravating.
Aaron