Do students have the right to see how their papers were graded? Note: You may refer previous revisions for more context.

I read Academia varies more than you think it does, but in any school or university I've been to or heard of, students can always see how they were graded for any assignment. Or, at least, if the school won't let them keep it, but they will at least let the students view it (usually final exams).
I believe it's every student's right to know how e was graded on, well, a graded requirement. (see Dan Fox and David Hill's answers) The only exception I can think of is Educational Testing Service, which administers the TOEFL and GRE, but it's not really a school or anything.
Recently, my sibling was a little surprised with a grade on a paper and wants to know about how their particular paper was graded. But when my sibling tried to ask to view the marking of the paper, this was the reply:

Are you an exchange student? [University] does not provide marks to students after the examination. The only thing that can be released is the Grade or Pass/Fail. Giving you the marks would be a violation of the regulations. In fact, all such information will be destroyed after a period of time. You can try asking other teachers about marks, they will also tell you the same.

(My sibling is not an exchange student.)
Main question: Do/Should (see here also) students have the right to see their how exams were graded?
Some guide questions for the main question:

Is this policy unconventional or unethical or unfair? Based on
Corvus' answer to this
question
or Dan Fox's answer to this
question,
I kind of think my sibling's university's policy is unconventional
or something.

How will any student get feedback on their communication or their mistakes if they do not see any of the marking of their work?

Is it unconventional, unethical or unfair to tell them to ask other teachers rather than point to the specific university regulations?

Is it unconventional, unethical or unfair to not have specific university regulations on this matter?
I doubt that this is a case of a student &quot;offending&quot; an individual professor and more one of rules in place that may not make sense and that you may not approve of, but still, rules.
I don't like, personally, such rules. I think they are wrong, but an individual professor has little actual control over rule making. They may not be willing to break the rules, especially if they are a junior faculty member.
Personally, I probably wouldn't give back final exams, though I did give back all others. But I would certainly let a student look over the grading. But I was bound by no such rules.
And, note that, depending on the scale of the institution, it might be very difficult to permit students access to final exams. When I was a TA, we graded Calculus finals as a group, with each TA grading only one problem. So, a student's grade was an amalgam of judgements. We were guided by a rubric, of course. But the professor didn't grade the finals and so might find it difficult to respond to exactly why a point (or ten) was lost. Smaller institutions can &quot;afford&quot; a more personal touch and usually strive to do so. It should be (perfect world) possible for larger ones to do so also, but often don't. And if there were a few hundred students, it is difficult to respond to individuals, just for the time it takes. Ideal? No.
Intermediate exams are a different matter, in my view, since they can and should be used to guide the student's learning. But, Rules.
And usually, by enrolling in a university, the student makes an implicit (at least) agreement to abide by the rules in place.