sounds like it, but given usb plug-n-play I'm sure you could make a more persistent version. And also clearing your cache won't invalidate all your web session

sounds like it, but given usb plug-n-play I'm sure you could make a more persistent version. And also clearing your cache won't invalidate all your web sessions that they could have stolen. You'll want to find every site you were logged into, and explicitly log out. Otherwise those stolen cookies will still be valid, unless the website does some sort of channel-id thing to bind cookies to the particular computer (which I'm not sure is possible beyond experimental browser features, and certainly is not common practice)