There are a few reasons why people don't commit acts of violence or commit a crime of theft or anything else against the law.
The MAIN 2 reasons are this: You are a moral, caring, human that was raised to understand the difference between right and wrong and you have the ability to reason. Or you are not willing to pay for your crimes.
If the 1st one fails because you are unable to comprehend good vs evil, or you were born without compassion and emotion and your parents didn't try/were unable to instill in you how to be a good person, then we have to rely on punishment and deterrent. When cities stop arresting or detaining, when prosecutors let criminals go with no consequences, this will continue to get worse. Much worse.
Always be aware of your surroundings.