Been thinking about this today and I agree. If the actionability is reliant on a human in the loop making a decision to create some incident (e.g. traffic stop) then there is a limit to the surveillance while still scaling the law to apply to our growing population.
In that vein, I wouldn't be 100% against Flock cameras if their purpose was limited.
The problem in the concept is that they store all license plate hits for later retrieval regardless of if anything is actively tying that license plate to some form of illegal activity. Even with a short retention window, this is mass surveillance because it allows later viewing of hits based on any kind of search given. And you can never limit that search query in a 100% effective manner, but you could very well tell police departments "tough luck, we only have hits if the plate was involved in something at the time of scan".
If an officer was standing next to every Flock camera in America, the public would be hyper aware of the situation we are now in.
Mass, warrantless, and perpetual surveillance is incompatible with liberty and unacceptable to the vast majority of Americans.
It has to be stopped, or we are doomed.