It's not that black and white but it's not that complex of an issue either.
Act - https://www.aclu.org/other/model-act-regulating-use-wearable..., White Paper - https://www.aclu.org/other/police-body-mounted-cameras-right...
Honestly, privacy is nearly dead anyway. I'm not happy about it but there are databases with enough information on us to steal anyone's identity. With that level of information already existing... it seems kind of silly that what we're most worried about with police cameras basically comes down to embarrassment.
It's also weird how hacker news has forgotten that Google Street View has tons of pictures of naked people with automatically blurred faces. Same for Google Maps/Earth.
As another poster said, this is solvable. Just will require more than a few rules.
I get it. Most of us are programmers, so we think we can setup a pretty solid set of rules for when something applies. Maybe some of us can. And when that perfect ruleset is found, it will be awesome. However, it is a lot more fluid and discretion is not necessarily a bad thing.