If cyclists go to head cams and cherry pick bad road use by drivers it's just going to lead to tit for tat from drivers with dash cams.
Bear in mind many haulage firms and local bus companies are fitting cameras to record incidents, so any incident of car/hgv/bus vs cyclist
that is captured on the cyclists' camera ... may also be filmed on the vehicle as well.
My friends haulage company has two cameras on each truck as per the request of his insurers.
Which leads me on to the small detail that if you are involved in a near miss, you may be able to contact the company involved and ask
to view their video recordings prior to making a complaint.