DashCams / Helmet Cams - Good or Bad

[fazersharp]

A case in point - only a few days ago I was filtering between lanes 2 and 3 on the M6, I come across a guy also filtering.  A car ahead of us was clearly distracted, drifting to the white line etc (traffic was doing maybe 10-20 mph).  The rider in front (with a GoPro on his helmet) had clearly decided to get it on camera, slowed and looked at the licence plate first, then accelerated along side to get a look in at the driver.  He actually clipped the wing mirror of a car in lane 2 as he was concentrating on looking to his right at the driver.

This is it for me that gets my goat where its the rider with the cam that becomes the problem.
I am thinking of getting one for insurance proof use, I have no intention of uploading crap to utube or filming my own riding.