Newark, Delaware, 6-year-old Zachary Christie was so excited about the all-in-one eating tool he got when he joined the Cub Scouts that he brought it to school so he could use it at lunch. Anyone familiar with the "zero tolerance" idiocy that has swept the nation in the last decade can guess what happened after that. The only real question is whether Zachary was expelled or merely suspended. Answer: He was suspended for 45 days. But he might have been better off if he had been expelled, because a new state law gives school officials some discretion in expulsion cases involving students who unknowingly violate rules against weapons and drugs. The legislators neglected to address suspensions. The front-page New York Times story about the incident quotes "zero tolerance" defenders who say distinguishing among offenders based on intent can be dangerous:

Some school administrators argue that it is difficult to distinguish innocent pranks and mistakes from more serious threats, and that the policies must be strict to protect students.

"There is no parent who wants to get a phone call where they hear that their child no longer has two good seeing eyes because there was a scuffle and someone pulled out a knife," said George Evans, the president of the Christina district's school board....

Charles P. Ewing, a professor of law and psychology at the University at Buffalo Law School who has written about school safety issues, said he favored a strict zero-tolerance approach.

"There are still serious threats every day in schools," Dr. Ewing said, adding that giving school officials discretion holds the potential for discrimination and requires the kind of threat assessments that only law enforcement is equipped to make.

Evans' concern might be grounds for a uniform rule against knives, but it does not justify treating all violators the same, regardless of age or intent. And contrary to Ewing, you don't need police training to tell the difference between an overeager Cub Scout with a nifty camping tool and a budding thug who brings a switchblade to school in anticipation of a fight.

Jacob Sullum is a Senior Editor at Reason magazine. Read more at reason.com.