People who commit low-level crime are far far more likely to commit serious crime than the general population. Sometimes here the police will set up roadblocks and stop every car and check for tax/MOT/insurance. Drivers found without these get checked out properly and the police find a large number of outstanding fines/arrest warrants/more serious naughtiness.
Also, not getting punished for low-level stuff when young helps instill a sense of 'I'll never get caught' in the minds of the anti-social, which helps move them onto more serious stuff.
We need an army of Judge Dredds wandering about executing people for stuff and that. Once the bodies start piling up we might start seeing fewer crisp packets blowing about.
FACT!