Credit to 9to5Mac for discovering the flaw which was being discussed on a German Apple fan forum, allowing the last application used before the device was locked to be accessed, but not nearly enough to reach the main home screen. I guess for your own peace of mind, ditch the Smart Cover, or make it a habit to run an inane piece of software or app such as Angry Birds before you close your iPad 2 with the Smart Cover.
To check out this exploit, hold down the power button on the iPad 2 until the ‘Turn Off’ slider appears, put on the Smart Cover, remove the Smart Cover, followed by hitting the ‘Cancel’ button that’s makes an appearance. Could this be the new Up, Up, Down, Down, Left, Left, Right, Right, A, B, A, B, Select and Start?