I know a guy who used to commit criminal mischief, grand larceny including stolen vehicles and so on before his 18th birthday. He did got away with these and got warning from judge and this pissed off plenty of cops. After he turned 18 years old, he never re-commit any of these crimes and now is happily with his future wife and two kids and is currently instructor at college. If you met that guy I know, you will never know he had committed such crimes.
Sometimes kids who thinks they can outsmart system before they become 18 years, sadly that can happen and usually they won't do such after they reach 18. That is why I believe jive offenders deserves second chance.