You didn't answer my question.They may have come to realize the wrongness of some actions. Others they decided not to do no more or they may do it again and try not to get caught. I would ask one grandchild if God liked what he did. He told me no.
I believe in life in prison without parole for murder. I still do not believe in the death penalty for reasons stated before. One person innocently put to death is one too many. Also Jesus tells me I am also a sinner and not worthy to judge others to death. I trust God to judge and give the punishment. Also believe God loves all sinners and wants give them time to believe and repent. "The last shall be first..." Mt 20:16.
There is a time when children have no clear understanding of good and bad. "Moreover your little ones, which ye said should be a prey, and your children, which in that day had no knowledge between good and evil, they shall go in thither, and unto them will I give it, and they shall possess it" (Deut. 1:39). At first when punished they may not understand why. Therefore they may do the same thing again even when knowing they will be punished. But as they get older they will understand why.
As for punishment my Dad would get drunk and beat me severely with a belt. I have not the heart to do the same. My dear departed wife would give the physical punishment.
Do you know how God commands parents to punish their children?
If so, what does He tell them to do?