That's a lot of reading in those links. When I think of "friction" type sway control, I think of a device that involves a clamping force to create friction. The dual cam does not use this principle. From reading on other forums, that's the understanding I've gotten too.
Of course there is some friction involved because of the force imparted on the cams by the spring bar, but the way I see it, the crooks on the bars "roll" up and down on the cams in relation to swaying. This imparts a horizontal force on the sloped sides of the crooks which in turn exerts a force (in opposite directions on each side) to straighten out the TV and trailer in relation to each other. I'm an engineer by training but not a hitch expert so maybe I am dead wrong, or worse even... Come to think of it, the dual cam arrangement ought to work even if you had roller bearings in place of the cams, except that the bars would probably need more tension.
Is there factual engineering info. from the manufacturer that supports the claims here? Just being curious.