Since the launch of iOS 5 the iPad 2 has gained a security issue which allows a smartcover, or any other magnet, to be used to bypass the lock screen.
Although some of the things you can do when bypassing the lockscreen are limited, if you leave an app open on your device it can allow users to get in and delete apps or use the last app you had open. If you close out the app you are last in then the user can still delete apps and look at what you have (and search spotlight), the user cannot open apps.




