Given that the iPad doesn't have a security lock like many laptops do, this probably took some serious thinking. The iPad Lock is comprised of two parts: a hard plastic case and a steel cable that can be tethered to a sturdy, fixed object.
The system is designed to open in seconds when appropriately unlocked. If it is broken open by a thief, the iPad will inevitable incur serious damage, essentially destroying your iPad but saving your private information and foiling the thief's plans at the same time.
All of this certainly makes the iPad less compact, but also less portable - which is sort of the point.