Sgt_Kickaxe - 2:52 am on Oct 19, 2011 (gmt 0)
They can also receive an aggregated list of the top 1,000 search queries that drove traffic to their site for each of the past 30 days through Google Webmaster Tools.
Google knows why people were tracking keywords outside of GWT by tapping search parameters and they know they aren't giving the same level of detail in GWT.
Do you know all of the keywords that drove traffic to any given page thanks to GWT? No, not all are displayed and it's not broken down that way for you.
Anyway, it won't be difficult to throw an error message now saying "We're sorry, it appears that your logged into a Google account that is interfering with our website, please log out and refresh the page".