Social normalization of deviance means that people within the organization become so much accustomed to a deviant behaviour that they don't consider it as deviant, despite the fact that they far exceed their own rules for the elementary safety. But it is a complex process with some kind of organizational acceptance. The people outside see the situation as deviant whereas the people inside get accustomed to it and do not. The more they do it, the more they get accustomed. For instance in the Challenger case there were design flaws in the famous "O-rings," although they considered that by design the O-rings would not be damaged.

The point is that normalization of deviance is a gradual process that leads to a situation where unacceptable practices or standards become acceptable, and flagrant violations of procedure become normal -- despite that fact that everyone involved knows better.

I think this is a useful term for IT security professionals.