After a student drops out of high school, she becomes labeled a drop-out, and her subsequent actions and choices are explained in terms of this label. those subsequent actions are called:

Those subsequent actions are called: Secondary deviance

Secondary deviance is a process of integrating wrong doings into the concept that validate the actions/behavior.
When the student labeled as a drop-out, he/she will phone to get a validation for al other bad behaviors consistent to that label.

An informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.