Worse, as ad networks can--and do--block publishers for click fraud.

well they will be able to identify that the user is responsible, not the host. hopefully

How?

Same way they do now. They don't publicize the algorithms i believe

http://www.google.com/ads/adtrafficquality/invalid-click-pro...

I think its an attempt at anarchism. This on any scale might render their data useless. Of course they might just ignore all data from this user meaning it changes nothing.