It seems like cam cleats would be nice to use to hang fenders from the
boat. Stick the line in the cam cleat "too long", then pull on the end
to zip it up backwards until the fender is at the correct height for
the boat/pier/rub rail, then let go, the teeth gripping the line to
prevent the fender from going lower.

I have found two great products:

http://www.schaefermarine.com/hardware.asp (Go to Deck Hardware then
Sure Grip)

and

http://www.harkenstore.com/uniface.urd/SCCYSPW1

I emailed a tech support guy at Schafer and he says that this
arrangement does not work, the fender line tending to get out of the
grip of the teeth.

Anyone want to contradict that, has used cam cleats in this
application?

Mitch