[PvK]

Imagine you were really going to do something stupid like make a heavily-armed starfaring warship controlled by a computer, and assumed it would always remain loyal to your side. You'd certainly want to make as sure you could that it would not be susceptible to being sent impostor command messages. After all, if someone figured out how to tell it to do things, they'd be in control of it (effectively, a mutiny). So you'd need to program it to sometimes be suspicious, and decide some such signals were hostile takeover attempts... which could lead to false calculations of what was a hostile takeover rather than a valid command... which if it happened, could effectively be like a mutiny... etc, etc...