This one should be easy ...
Imagine you create a robot, that reacts on vocal orders ...
Then it hit you, anybody could use your robot ... so you decide to code your comands into reciting verses from your favorite performance ...
But then it hit you, anybody who will find those lines and fire out that they are used for can do the same ... and so you decide to hide there a trap line, that will tun your robot into "kill on sight" mode ...
And voila.
If someone gets to your robot and figure out how to control it ... and if he pick wrong line ... he will be reduced to dust. :3 Its safety mechanism.
