I have sent a strongly-worded email pointing out that this is unacceptable, asking the student to rewrite the post, and saying that I'm not turning the matter over to the honor council only because I realize I asked the student to write the post first thing, so I could put hir in a group, and perhaps (s)he hasn't read the syllabus, with its dire warnings about plagiarism (and immediately turning over all cases of deliberate plagiarism to the honor council), yet.
Any bets on what happens next? Does (s)he drop (still possible without loss of tuition, but not for long)? Protest innocence? Apologize, straighten up, and fly right from now on? (hey, a proffie can dream).