It seemed rather obvious to me that the best solution for your average municipal justice system is to arrest only the ones you can make an ironclad case against, then prosecute them to the fullest extent of the law, with no options for fines, probation, community service or suspended sentences, only hard time, be it only a few weeks or months.
If only a handful of these adorable scamps have to do a year in the pen, said city would see a rapid decline in organized disorder from the black bandana crowd.
You're on to something. I recall how the Kent State incident put a major damper on anti-war (Vietnam) protests. These things are only courageous when there is serious risk of injury, imprisonment or death involved. Without serious risk, it's only a lot of pissing into the wind.