google should allow banning ip's through adsense to protect against click fraud as it is google doesnot allow any other method for preventing click fraud from the publisher's point of view for specific clicks say some person is being robbed of adsense earnings by bad elements thorugh click fraud the only option one has to report to google may by that time his account will already be banned it would be nice if we could ban specific ip's through adsense say for a whole country or a city from where click fraud is generated helping both google and the adsense publisher
Wait IPV6 is going to replace IPV4 soon, then a PC can have as many ip addresses as it like. Believe me google's invalid click detection algorithm sucks . Use etheral to capture packet between your PC and google when you click an addvertisement, you will know why google algorithm to detect click fraud sucks big time.
I would rather consider this a responsibility of a site owner since it is quiet easy to ban IP or entire network classes by a site/server owner using iptables to protect your site/server.