I like the idea of a TEMPORARY city wide footage, say everything not part of an active investigation expunged after a month. It should in no way by indexed by the individuals or objects within it, but instead just the location and time.
If you are solving a crime, a human finding the suspects from the area, and tracking them out through the footage should be worth the results. If you aren't willing to spend that effort than it surely isn't a truly important thing you wanted to get from that data.
If you are solving a crime, a human finding the suspects from the area, and tracking them out through the footage should be worth the results. If you aren't willing to spend that effort than it surely isn't a truly important thing you wanted to get from that data.