Weapons of mass deactivation

ICBMs have no in-flight self destruct mechanism for a reason. The mechanism could be activated by the enemy and thus renders the weapon useless. May be this example fits not perfectly, but it shows the problem you have with self-destruct mechanisms. A similar mechanism will be integrated into the WGA subsystem of Windows in upcoming updates as reported by Bruce Schneiers weblog. I don´t want even think about a worm that deactivates millions of Windows licences throughout the world at the same day because of an exploit in this functions. This would the end of enduser computing as we know it ;)