Google's fraud

http://bigpicture.typepad.com/comments/2008/04/googles-black-b.html

Read the comments. There are people complaining about their Adsense rate getting cut 75%, there are people who's account was banned. All sort of stuff.

I agree that google's revenue is basically a black-box. Actually, does the advertiser have the ability to check how many click thru's they have? I mean, by them having so many server farms, is it possible for them to click into their advertisers websites?