I'm not usually for mass surveillance, but I've seen reports of successfully altered behavior by cops who wear body cameras. Perhaps it would be a good idea to have all cops wear such cameras as a mandatory prop as long as they're on duty.
It is a good suggestion to keep the cops under surveillance. But is it practical to make all of them wear body cams? The initial cost, as well as maintenance will be huge. And there is no guarantee that they will not damage / tweak them. Also we need more manpower to manually monitor all of them.