>It will never happen, but if a law was passed that when the video is unavailable, the citizen's report is presumed to be true and complete, I'll bet those cameras would suddenly get a lot more reliable.
Indeed. This is the missing key ingredient.
I once got pulled over for speeding while driving doing the speed limit. I saw the cop coming down the road toward me, and had slowed down by the time he'd u-turned and pulled up behind me to tail me. I'd been speeding before, but this wasn't what he claimed in court - he said I was doing 78 (written statement) 87 (oral statement) while tailing me on the I-5.
I'd requested the camera footage of the event, but it mysteriously wasn't available to me.
So it was just the cop's word against mine, and the court will side with a cop every time, even though there was a serious discrepancy between his written and oral statement, and his video footage wasn't provided to me.
If the law stated that the presumption would go the other way (favoring the citizen over the cop) when video evidence disappears, it would eliminate the easiest source of police abuse of these tools.