Part of it comes from personal experience with a very low minority of LEOs that had a poor interaction with me and saw the facts as complete opposite as I did. This can get you in a lot of trouble when you're young and poor.
Here is an interesting article on the impact of having police officers in California use not only dashcams, but wearable cameras that document the entire public / LEO encounter:
http://www.nytimes.com/2013/04/07/busin ... d=all&_r=1&" onclick="window.open(this.href);return false;
If this is "liberal" media junk, forgive me, I really don't know if the NYtimes is liberal or conservative, and I don't really care in this circumstance as I think the results are striking.
Partial results:
1) 88 percent decline in the number of complaints filed against officers, compared with the 12 months before the study, to 3 from 24.
2) 60% reduction in use of force by officers that are recorded.
I hope most modern policing moves this way. It'll go along way to restore public trust and protect good officers..“There are many police officers who’ve had a cloud fall over them because of an unfounded accusation of abuse,” he said. “Now police officers won’t have to worry so much about that kind of thing.”