No one has to discriminate against any individual student who comes to night classes. The rules and traditional patterns do that. There is no human perpetrator who is discriminating against any individual. Institutional discrimination is far more complex and more difficult to combat than overt discrimination where there is a perpetrator. Sovereign power goes with titles and overt authority to dictate rules and regulations.
Disciplinary power resides in the rules, norms, and expectations for traditional performance.
Institutional discrimination relies on disciplinary power. Since disciplinary power seems to apply the same rules to everyone, there seems to be little discrimination. But when the rules grew from contexts in which there was discrimination, the unstated assumptions carry those discriminatory contexts right along with the rules in present contexts. Further readings on institutional racism . The importance of telling the story of what racism feels like.