did nothing to stop it. The parallel here would be if a school required students to accept accept use of TurnItIn - which is a legitimate action (consider the requirement to sign a non-compete or non-disclosure agreement as a legitimate requirement for employment, or an agreement to sign an academic honesty statement) - in order to be part of the student body.
These are not nearly parallel. You're asking students to send their papers to a for-profit company *not of their own choosing* for assessment. That's radically different from asking them to sign an academic honesty statement, and certainly different from the legal mire that is non-compete and non-disclosure agreements. Schools already provide a legitimate plagiarism detection tool - they're called "faculty". ;-) [If those faculty don't feel that they're able to detect plagiarism - well, that's another track of discussion.] --e