Individuals managing their own law and order is strongly frowned upon in most cultures.

Communities may provide their own training and personnel, but they're generally subject to the laws of their state/nation/etc.

Local municipalities pass their own ordinances, laws, regulations, etc all the time. They just cannot contradict the laws of the state / federal. That is absolutely communities managing their own affairs, writing their own local policy.

That's a good point. I was thinking on a community level, and expanding the group size as necessary in order to provide these things... but it does tend to be a bottom up type of thing (as opposed to top down).

Law creation is probably the biggest outlier though