I’d be willing to run a social experiment if they could find a community that wanted to do it. It would be a true ghetto, of course, because it would have to fenced off from civil, policed society. But, if a group could be found that wanted to live in a no-police community, let them have at it, so long as we can control outside collateral damage.
Such a community could never voluntarily exist, because the predators that want no police are parasites. Without a productive, or at least wealth (even if welfare is the source) possessing community to prey on, they would have no means of support.
You also have to stipulate no welfare or other assistance.