The only reason police originally objected to it was the expense and it's just one more thing cops have to have on them to work.
Years ago I used to work at a music studio teaching guitar, and one time I had a local police officer as a student. The lessons were a half hour and he spent the first ten minutes of that lesson taking off all the crap he had on. The gun belt, the leg protectors, the bullet proof vest. I asked him how he ran with all that crap on if he was chasing somebody?
But videos are the thing of the future. In fact I'm a truck driver and last year I purchased a dash cam because of all the stupid shit people constantly do in front of me. It's has a suction cup mount so I can place it in the back window behind the seats. This way you can not only see what's going on outside the truck, but what I'm doing at the time if something did happen. It even has a GPS in it that calculates your speed, and it's pretty damn accurate too. Thank God I never had to use it yet, but it's the best $130.00 bucks I ever spent just for the peace of mind.