Regarding your fourth line about pairing officers with volunteers, this happens in (some/all?) UK constabularies, for example: https://www.lancashire.police.uk/ridealong

On a related note, we also have volunteer Independent Monitoring Boards for prisons: https://www.gov.uk/volunteer-to-check-standards-in-prison

And voluntary magistrates' courts which try all cases first (although they pass serious ones on to the Crown Court): https://www.gov.uk/become-magistrate

And Patient Participation Groups for all GP practices: https://www.napp.org.uk/ppgintro.html

I don't know if any of these are also the case in the US, and the UK definitely has problems of its own, but it does seem to be leaps and bounds ahead in terms of citizen oversight and institutional transparency.