I once stopped to try and help a pedestrian, down and unconscious after a hit and run, and watched EMS arrive and bundle her onto a back board without even thinking about stabilizing her neck. I murmured a polite suggestion, which they ignored. Intervening with professionals and officers is generally a bad idea, but my faith in people doing the right thing has been, shall we say, tempered by medical training and world experience.
The cops around here aren't perfect, but are a great net positive for cyclists.