The problem is Bayesian priors look an awful lot like racism to the unaided eye, enough so that it's really hard to justify them. Or maybe it's racism masquerading as a Bayesian prior. I don't see how to know for sure either way.
Also if such devices (and law enforcement) worked well to reduce crime, the crime would move to less-surveilled areas. We don't see that happening anywhere.
You are still claiming that crime is conserved. It's not possible, even likely, that a reduced cost-benefit for committing crime shifts preferences toward some non-criminal activity with a more attractive risk-reward profile?
