A quick side journey into high school athletics....IMO, it follows that KA did not go to his own school tent, either because he was prohibited from competing due to a prior incident at school, or he failed to qualify for the event (by his performance), or both.
District meets serve as the "pre qualifiers" for Area, then Regional, then State meets.
So...qualification by performance for district meets is automatic. If one is on the team, and one is eligible to participate discipline and grade wise, one gets to compete. The "must qualify to compete" concept starts at Area, and continues to Regional, and State.
But.... the general "qualified if on the team" concept can be over ridden by individual coaches judgments when making selections for say, who will be on a relay team verse individual sprints, who gets to compete in what additional events (there is a maximum number per student) etc.
Following your "eligible to compete" possibility, it is possible that KA was still over all eligible to compete grade and discipline wise, but was removed from a coveted spot on a relay team, or maybe not permitted to max out his event eligibility for some reason or another.