If there are consequences in school, for problem students and problem parents, will it benefit the society.?

I am a teacher. most experienced teachers can predict how a problem student will behave at 18 or after. Such students harm the education of other students in the class. Also motivation of a devoted teacher also becomes low. it does not affect teachers who only care for money. The parents either do not care, or blame the teacher because their angel can never do wrong. In my experience, if such students are forced to do a lot of extra home work, they reform in just 3 days. This will reduce the number of welfare drones and criminals. I believe there should be consequences that are more painful than studying and behaving decently, for both problem children and problem parents . For children less than 12 years of age, we may ignore but after that every year their work and behavior should improve. This will also improve children from uneducated families. what are the harms in this approach?