Of course, if you don't go by the book and fail, your career just got significantly shorter. This is a pretty good way to sort those who can exercise good judgment from those who can't, althoughh it is a little bit hard on the troops at times.
In the less rigid civilian sphere, breaking the rules again has its place in civil disobedience. Social rules are more frequently ignored, and the most successful such experiments often become mainstream, just as in the military. Rule-breaking is a little like mutation: You don't want a lot of it, but you can't evolve or adapt without it.
So when users are sneaking stuff onto IT networks, I have to think at least half the problem is an inflexible policy by IT management, designed to make the manager's job easier rather than the users'. And that, ultimately, is bad business.
If I found a Microsoft machine on my network, it would be removed, and the person who added it to the net would be fired. Microsoft machines are not compatible with our applications, and most of our software is poorly supported on Wintel machines. Therefore, we have no use for Microsoft renegades.