Plagiarism is in fact provoked and produced by the type of traditional assignments given to students. Instead of asking them to discuss with pros and cons, and even including a third point of view, any subject or topic and grading the papers on the way the argumentation is built, teachers still give one-sided topics and expect a traditional essay which is the best way to get plagiarism (copy and paste, or copy translate and paste).
I just got an email starting with “my very expensive” translated from French “mon très cher” instead of the awkward “my very dear.” Translating machines are so funny at times.
But when you know that Google is able to give you the source of these plagiarized papers with a simple sequence of six or ten suspicious words from any paper with the originals, the Internet addresses, etc. Even in foreign languages.
If the papers are in digital form, which is even better, then you can do the search directly from your computer: select and search.