Should one cite during university exams? As the title suggests, it's not a usual practice but should one do it? All I know that one can study for an exam and simply write the answers needed in order to succeed, no one tells us to include the names of authors of the ideas we memorized to write (except rarely).
In most technical university exams, there is no expectation of citations since the concepts are typically "textbook-level" material and thus established as part of the "common knowledge" of a subject.  Such information is rarely cited in the scientific literature, as it taken to be part of the shared background knowledge that has been so accepted as to no longer require explicit crediting.  For example, Newton is almost never cited when discussing basic physics.

In a literature or similar humanities course, on the other hand, the subject of an exam may explicitly be discussion and analysis of ideas presented by others. In this case, one would be typically be expected to at least informally cite the people whose ideas are being discussed, e.g.:


  Rawls' theory of justice, while more sophisticated than the simple utilitarianism of Locke, is considerably more difficult to comprehend"


Full formal citation, however, is typically both impractical and not useful within the scope of an exam.

Where business courses fall on this spectrum will depend on the course: when discussing case studies, I would expect informal citation to be appropriate, whereas an operational research and statistics course would more likely fall into the technical end of the spectrum where there are no citations.