Pretty much all school punishments are unfair and contrary to any concept of human rights as there is no such thing as a fair tribunal. You cannot ask for a hearing, most punishments are given out on the fiat of a teacher who is not required to present any evidence for it. Also, a large number of punishments are not for specific breaches of codes (such as being late), but for subjective matters (such as rowdy behaviour). So in effect, a teacher decides that a particular behaviour is a breach, and without the need for any further authority, gives out a punishment of their own choosing, for which the subject has no redress and no right to tribunal.
Further, many (if not most) schools still practise collective punishment. Again, a gross breach of human rights.