Laws just say what you can and can't do and you will be punished if you get caught violating those rules. There is no cosmic entity that will stop or prevent a crime from happening. Very rarely do police arrive in time to stop something. If it's a bank robbery sure they might surround the area, but if someone is getting mugged or beaten up chances are the thugs doing it have already fled by the time you arrive. They also taught us that you can drive down a street and not see anything, and it true. When you are driving you are mostly focusing on the road, not some much on what's going on to the sides of you. Plus people learn to spot police cars really fast and the moment that guy with a slim jim trying to break into car sees a patrol car he his going to try and blend in or hide. Then you are going to get a call later saying there is an autotheft being a reported and you will think "son of bitch I just drove down that street". Patrol is basically only a brief deterrent.
Two things you are probably guaranteed to roll up on are robberies at a bank or store and a domestic dispute between couples.
Also to in order to punish someone for breaking the law, you have to catch them first. What I hate about the cop shows is that they are so unrealistic. You have the crying wife who found out that her husband is dead and the confident detectives walks and says "Don't worry mam, I promise do everything in my power to find this man and we'll catch him". First of all you never make promises, and second unlike the TV shows where the detectives use forensics and smart guesses and they catch the bad guy in 24 hours simply does not happen in real life. In real life detectives are working multiple cases at once and don't have the time to focus on just one case. Forensics is expensive, it's not worth it to have a lab come out for every little crime. Most of the time those cases don't even get solved for many reasons like be buried under tons of work, or the suspect just drops of the earth and is living somewhere else under a new name, maybe there is insufficient evidence to, maybe the guy who did it died. Heck my last professor said he still has a stack of cold cases from the 90s and early 2000s.
