The free market will solve this problem very quickly.
Enough click fraud will reduce the number of people who advertise with this method very quickly because they’ll see bad results. Cost per click will go down.
To see this in action, compare the average CPC at 7search and at Xuppa for the keyword “online casino”.
Everyone needs to monitor their ROI using any particular PPC engine very closely. Fraud PPC engines, and engines that encourage and support PPC fraud, will go out of business quickly.