I wish statements like this weren't needed, but they are, and I appreciate that you wrote one.
Is this story pinned? If not, I'd suggest that you pin or otherwise keep it front and center. At an excellent university where I taught magazine writing, the policy was: You had to explain to students at the beginning of every course what plagiarism was and what the consequences of it would be.
Most of my students were journalism majors who no doubt heard the plagiarism spiel many times by graduation. But I see and support the university's point: If you don't do it and students plagiarize, they can come back at you or the school and insist they didn't know that what they did was wrong.