I was dead against police forces setting up these "send in your dashcam" things as I thought it would prompt thousands of people reporting people for minor issues on the road. However, it seems like it's been implemented well, and although you do get quite a few "I'VE GOT YOU ON CAMERA!!11!!" crazies emailing in, the majority of people are reporting genuine, wilful **** driving.
I was chatting with the guy in my force that deals with them and he showed me quite a few of the clips that get sent in. Most of them are absolutely ****ing nuts and the drivers deserved to be prosecuted (overtaking around blind bends, undertaking someone on single carriageway on the grass bank(!), people being on their phones and pulling out without looking, people overtaking a queue of cars at traffic lights, then going through the red light on the wrong side of the road etc etc). It's really scary how mental some of the footage is.
There are several filters to make sure that the ones that deserve to be prosecuted are, and the ones which are just people making mistakes are dealt with sensibly also. The first filter is normally from the owner of the dashcam - a lot of the six-of-one cases filter themselves out because the owner of the dashcam makes themselves look as bad, if not worse than the person they would report. No one is going to send in footage where they are ****** and jeffing at the other driver, sticking fingers up, flashing, getting up their arse and the usual thing people do when they've been wronged on the road.
For the dashcam owners who manage to restrain themselves, but still send in crap where someone has made a simple mistake, they normally are placated because the police will send the other driver an "advisory letter" saying, basically, "someone sent in footage of you going through a no entry sign, just be more careful in future".
Like i said, it seems to work well.