<p>“Because it doesn’t matter whether the student is lying or not.”</p>
<p>I agree. The results matter.</p>
<p>You’re doomed if you tell undergrads there is no hard deadline. Always give them a hard deadline. The next round of editing has to begin on date X. Either they meet that deadline or they don’t. But you’re going to have endless trouble if you just say “as soon as you can after break” or whatever the soft deadline was.</p>