Dave, the question of shaving isn't just a question of 1 signup = 1 pay. There are other ways to shave. Would you also say your program tracks all hits, doesn't geo redirect any surfers, doesn't pop consoles on top of traffic, and those consoles are all 100% to the benefit of the webmaster sending the traffic?
I don't ask this to attack - I truly don't know the answer, so I figued I would ask and see what you have to say...
Alex