I asked 2 cops in a patrol car if I could install cameras on my own and how I should go about it. They said they don't mind them. Officially it's illegal unless you have a permit, but it's so widespread and the law is so unenforced that it's practically 99.99% legal.
I can point a few cameras to the street and record everything 24/7. When I'm on a bus I'm being recorded by a few cameras. On most bus/tram/subway stops there are cameras. In stores and public buildings there are cameras. Most cars have cameras for insurance or general safety concerns. Self-driving cars would have to have cameras, as well as delivery robots.
If we accept this shitty reality, why shouldn't I wear a camera and a mic, too?