Should Professors Tell Students That They Will Be Checking To See If Papers Are Plagiarized?

The following question was posed to Randy Cohen who does the column, The Ethicist, for the New York Times Magazine. 

When my daughter and her fellow college students handed in term papers, their professor had them submit their work to Turnitin.com, a Web site that detects plagiarism, something he had never done before. This has a whiff of entrapment. Shouldn’t the prof have announced in advance that this would be required, giving the class a chance to clean up its work?

I'd be curious to hear what other teachers think. I am stunned that the parent is not upset that her daughter and other students might be cheating but instead believes the professor acted unethically by not telling them that he would be checking for plagiarism.

Comments

[Dale]

The parent is saying that he believes most of the students are cheating, but it's just a matter of "cleaning" things up. Cheating is evidently OK with him.
"Entrapment" would involve tempting students to cheat in the first place; this isn't entrapment.
On the other hand, unless the professor is mainly interested in catching (as opposed to preventing) plagiarism, he should announce the Turnitin twist beforehand. Personally, I'd rather prevent; much less work.
Dale

[Dr. Delaney Kirk]

I'm with you, Dale. It's much easier to prevent cheating than to deal with the paperwork afterwards!

[Amy]

I use turnitin.com for almost all of my papers that students submit. However, I use it more for prevention than for detection. I allow students to see their originality reports and resubmit their papers if needed. I have found that some professors don't understand the originality reports though and believe that anything above zero percent is plagiarism. For me, turnitin is only one piece of a larger conversation about writing, research, and authority as well as documentation.