Discipline in school
I think there are two broad categories of disciplinary approach that teachers can follow when facing problematic or bad behaving pupils: casual and severe castigation. A casual punishment, such as a warning, can be used at the first occurrence of misbehavior or for minor offences, whereas severe punishments, such as suspension, should be used when the children recklessly persevere in their misdoings or in case of grave offence.
One advantage of a casual castigation may be that the student has the opportunity to understand what he did wrong, and try to do better, without really going into big trouble. The main disadvantage probably is that such form of discipline may not be enough and may result in the student continuing with his bad behavior. On the other hand, severe punishment make a stronger impression on the student and it also works as a deterrent for the castigated student, who will think it over before doing something bad again, and for the others as well.