I think what the GP meant was something along the lines of "Unauthorized security testing is indistiguishable from Malicious attack", in the sense that you cannot but expect the administrators of the system in question will react in alignment with their own goals. And you really have no control whether they perceive you as an ally or a threat.
Orthogonal to this fact is the question of what happens when an authority is brought in to solve the conflict. And something young hackers need to learn as early as possible is that you are not entitled to a due process in every possible context. It would be unlawful if you were not given the chance of a just trial in the context of a criminal or civil lawsuit, but this does not translate well into private institutions.
In particular case of a student unauthorized access within a university, this problem is compounded by the fact that such University and its representatives play the rules of prosecution, judge, jury and (sometimes) defense. You also have to consider that the people doing this are not professionals of law procurement but are pulled out of their real jobs to sort out some random mess, thus the only constrain is their common sense. I've even heard the first hand report of a case in my university where the faculty member supposedly playing "defense" was the most gung-ho about giving the boot to the guy in question (who ended up getting a one term suspension, but got to keep his scholarship, so it could have gone much worse).
This is probably not "fair", but it is the way it is and nobody seems interested enough to make it change. Education has a number of stakeholders with sometimes conflicting preferences and goals, so this is not a trivial problem.
But the point is that once your actions put you in the harms way, the abstract concepts of "fairness" and "proportionality of the punishment" are academic at best. My opinion is that legality is the bare minimum standard society imposes to keep barbarism at bay, but it is pretty rough itself. So it is in your best interest to conduct yourself in such a way that appeals to "the rules" happen as little as possible.