To add to Karen's comments, I have found that plagiarism and cheating do seem to be a function, in part, of immaturity.
Older students and more mature acting students see how it just isn't worth it and they do want to learn.
Many students know it's wrong, but think they can fool the teacher and since they haven't done any work, why not try . . . . We've all seen that as students and as teachers. It's an age old problem across cultures.
Susan in Shandong