It's a valid thought, honestly. Though seeing how tightly the police hold onto this tech once they have it makes it extremely difficult to just test the waters (and also requires vigilant public oversight, which the sheriffs' associations will fight tooth and nail).
Also having cops test this tech out, knowing they're going to be deliberately monitored to how often they use it for good reasons (e.g. child abductions) vs abuse it, would probably produce incredibly biased results. Think about it-- the experiment would be entirely self-serving: cops get to trumpet that it helped them for the legit crime here and there (and sitting through public safety committees, believe me, they will TRUMPET it), while showing that zero cases of misuse happened.
Ultimately, we have to think in systems: sure, ubiquitous surveillance would undoubtedly solve the horrific crime here and there, but at what cost to who we are as people? At what cost to how we protect minorities and the undocumented? At what cost to our already eroding public trust?