If you really wanted to cause chaos in the macro scale then having it randomly select Ads to click would be better one would think. If an Ad network has multiple Ads on a page that were clicked I would suspect it would be easy to form some type of filter heuristic for that particular set of users. It may cause a slight bit of obfuscation for that particular "user" on their side, but as for the over all success of an Ad campaign it would not be hard to remove those entities that selected ALL the Ads assuming more than one is served on a page from a given network.