If most of the advertisements were payed by click, I guess that some smart wizes would run remote software tools that increase the click rate artificially. So if the click rate would jump up and the sales rate does not, then marketing investors will either detect a fraudulent behavour or simply notice that the advertisement per pop-up is not effective and reduce their payment proportionally to match the sucess rate of actual sales. Since the placement of automatic pop-ups is basically cost free, I do not think that an automatic yes-clicker that raises the advertisement costs e is an effective tool to reduce pop-ups.