And yet no efforts at fecal recognition...
https://www.cnbc.com/2018/12/19/pooprints-brings-in-millions...
(As with many social ills, it's likely a very small number of repeat offenders – so identifying & appropriate addressing them in a prioritized manner is the best way to a solution.)
Just report the poop on 311 and they go clean it up. Yes it works.