Lol at the people justifying 'punishing' a 6 year old, who has no concept of timely responsibility at their respective age. The punishment, is utterly retarded and has no positive effect. Which is why it's retarded. I think 6th grade is a reasonable age to force time constraints on children.
Before that point, most of these students are nurtured and controlled by their teachers entirely and only can be late by their parents tardiness. Middle school is generally where kids have different classes with a variety of specialties that they are responsible for maintaining a locker and traveling from classroom to classroom. That is where 'punctuality' punishments should be given.







