"At the last DefCon event, one of the attendees, ‘Hamster’ showed off how the cookies sent by your computer when signing into a Google account can be copied, allowing the account to be cloned by the hacker, and all the implications that carried.
I’m pretty sure this happened to me whilst travelling through London’s Heathrow Airport recently. All was well when I boarded the flight home, but on landing, I had lost access to my Gmail account, the principle email account I use. A new password was in place, the secondary email (for password recovery) had been altered, and my security questions wiped." – Content courtesy of ITPro: Features: Google Mail Security