In the film, Billy (Sean Astin) leaves campus to bring information on the terrorists to the US Army. Billy takes too long to get back to the school for the hourly count of the students. The terrorists count the students but come up one short. So they count again. This time the terrorists grabs a student from the line and says "I already counted you!" (So we are to assume the students decided to send a kid from the front of the line to the back to get recounted in place of Billy)

The problem is the student they decided to get recounted was one of the four black kids, Hank (T.E. Russell), in a school of 100 white kids.

I would hope that the students would have been a little smarter and chosen a less obvious student to get recounted.