As I recall, this actually happened in Cincinnati a few years back with the black community protesting excessive police violence in the hood. The police stopped "policing" in the hood and guess what happened to the crime stats?
Violent crime stopped altogether?
I have a different theory.
Remember that black man who was shot by the officer in South Carolina a few months ago? The driver got out of his truck as ordered and when he was asked for his license, rather than telling the officer where it was, he abruptly turned around and reached into his vehicle.
The officer then panicked and shot the man. He was consequently relieved of duty for this, but the incident shows that in the wake of the Ferguson incident, some white police officers might be becoming more jumpy — and may even be disposed to over-react.
I maintain that this is all by design by those who profit economically and politically from sowing discord amongst the citizenry at all levels. Many are at the point wherein evidence means nothing to them as they filter everything through group identity.
That essentially means that Rule of Law is dead in favor of Might-Makes-Right. Let us remember who has the most weapons — the government.
It is entirely possible that in reaction to an increasing number of incidents, the local police forces will then be made subordinate to, if not taken over by, the Central government and some form of Martial Law instituted.
Remember that the Left is ultimately about power for its own sake.