This is a fascinating topic. At my school, we have one shared email account that everyone is encouraged to sent old tests to, then they are sorted into folders
1 Fall", "P3 Spring" etc. This has been happening since 1996. The professors nearly never use new test questions, so it's a bit of a give away.
There are more 'layers' to this topic than that done on the side of a student. Sharing old exams (which our dean of student affairs says is NOT cheating), people going on vacation so they take a test early then tell all their buddies about it, etc these sorts of things happen and of course we all have opinions.
However, at my school there is a whole additional layer on the side of the instructors. For example, if you as a student do not check every single response on every single exam (some exams have 140 questions, some weeks we have 4 exams) you will 'lose points' because there are problems on the prof's side such as:
1.) They often mis-grade our tests. This happens much more often than it should here, but it's just a known problem despite having a machine that grades our ScanTron forms.
2.) they actually switch our grades with other students and unless you do the work of the teacher to sort it out, you don't know heads from tails.
3.) Students argue against the teacher for a given answer in addition to the one deemed correct, and gain points this way. However, only those whom take the time to individually argue with the prof get the points. Despite the computer age, all those who also chose "B" do not get the points. Do you see the huge skewing?
4.) Redacted errors in questions are the responsibility of the student to (a.) hear about, (b.) track the prof down, and (c.) remind the blue-haired prof that they emailed that they would accept "B" as well some months ago. Frankly, most of us just stop caring and doing all this nonsense, accepting a B as opposed to a B+.
I know this is just my deadbeat faculty at my small school, but I reckon this happens to an extent in most places. Given that, I question how hugely grades matter. Of course I want to get passing grades, but the morale is so poor at my school beyond that I just want to quietly exit campus.
My opinion is that if 'smart' students are compelled to cheat, or if this is common at a given school one ought to look behind the mirror and question what is wrong with the school. Clearly a school could exist that is so grossly missing the point that most students find the risk of academic dishonesty a more appealing decision than just memorizing the ppt slideshows.
I do not encourage cheating, but I do know that such poor schools exist that this is a rational decision and can become the culture of a student body.