jomaxx - 5:17 pm on Oct 31, 2007 (gmt 0)

Risk of someone TRYING to do it: 100%. Risk of such an attack yielding a significant sum of money: probably nil.

I agree with martinibuster and justageek that Google has plenty of tools that help them identify anomalous traffic. In addition to the information sent directly from the browser, Google also has access to statistical behaviour patterns, conversion data, analytics data, toolbar data, its own search engine/spider data, registry data, etc. I'm not going to get any more specific than that, as I have no interest in helping the bad guys fine-tune their attacks.