I don't know if it's even OK for a cop to just randomly watch a random street corner without a specific reason to do so. If a cop was following a given person around all day every day without probable cause would this not be considered harassment? If we view the Flock Camera network as a single system is this not harassment?
Just to add context and not to comment on rightness, that was one of the early core purposes of policing--to ensure that a people in a particular public space (where either the people or the space are particularly vulnerable) are free from unwanted disturbance. Here is that exact concept shown in a painting from 172 years ago: https://en.wikipedia.org/wiki/The_Gleaners_(Jules_Breton).