If LEO themselves record everything all the time, the cameraman will just pan or zoom away from police abuse, and if not, records will just disappear. They have no incentive to present an accurate picture and plenty of incentive not to do so, esprit de corps etc.
I was hoping they continue in the tradition they are now, which has both saved them and gotten them in trouble in the past.
Currently they use dash mounted cameras with mics and they can't turn them off on some models. I was hoping they would have something like a helmet mounted GoPro or best mounted one. Yes, it won't see everything, but since they call 50 officers to a car ticket, someone will capture it.
Loss of tape should come with fines. Leo should be held to the highest of standards. No off duty for mistakes, you are fired.
The other case I heard where it helped them was some spoiled brats were drunk in public and called in a attempted rape charge. Tapes probed otherwise and had the girls talking about making the false claim in tape. They got busted pretty hard from what I recall.