Is this a FAIR punishment?

Emm.... I got a student from my second class who was made to clean the toilets for a week and not allowed to go home during weekends for 2 months. This is because he and another student were caught drinking Whiskey after school hours. It's the School's rules and regulations that the students are not allowed to drink while in the School. I heard that there were more students involved in the drinking session but only 2 were caught and punished.

Okie, I agree that it's the school rule that they broke and so, they should be punished. But should they be made to clean the toilets DURING lessons time? Can't they be made to clean the toilets after school ends? They are giving up learning time to do punishment. This, I do not agree. Moreover, this student of mine is considered one of the weaker students. He's already a borderline case during mid term exam and I'm sure he will have difficulty in catching up with the rest of the class if he misses more lessons.

What can I do? Put up a protest or petition for the School to amend its punishments?