Two of my sites seem to have been visited by a Google employee, the IP address is 18.104.22.168, I searched that & found this thread from the past :-[webmasterworld.com
On both occasions they added an item to the cart & checked out via Google Wallet (did not complete the sale). The visits were only 2 minutes apart over the two sites. These visits were in the early hours of the 10th (4.32AM GMT). Yesterday was poor but then again everyone seems to be in the same boat lately. Has anyone else affected by poor conversions had this IP visit? They also left an email address which was a Gmail account, I'm half tempted to email them!