A neighborhood in Seattle pretty much did what you’re talking about a few years ago, on a rudimentary zero-budget level. In fact I’ve been friends for years with one of the people who were deeply involved in it. But it wasn’t a “study” and I’m pretty sure nobody collected any statistics. And it only lasted a few months. I actually have no objection to it, what my comment said was that people aren’t going to do it. And look around you - the model is right there. But in a culture where fewer and fewer people even cook their own meals anymore, even fewer are willing to personally devote their valuable time to DIY law enforcement.