When cheating doesn't "count"

Another year, another futile attempt to make my academic dishonesty policy airtight. No matter how much I revise the policy, students try to wriggle through loopholes. A few examples:

1. An online upper-level writing course requires students to submit a proctored writing sample before the course begins, but a student submits a sample mostly copied from Wikipedia. The student says there's nothing I can do about it because it doesn't really "count" toward the grade, and besides, she would never cheat on something really important. I point out that I am obliged to report dishonest students to the provost, but if she drops the class before the semester begins, she will no longer be my student. That's called "fighting loopholes with loopholes."

2. In my sophomore-level literature classes, students are required to submit 20 reading comments over the course of the semester, each one worth 5 points, for a total of 100 available points. A few years ago a student copied and pasted just one of the comments from SparkNotes and then tried to shrug it off by saying, "It's only 5 points." The assignment sheet now specifies that plagiarizing any one reading comment will result in a 0 for the entire reading comment assignment--100 points. Loophole closed.

3. In most of my classes, students must submit drafts or receive an F on the final version of the paper, but the draft itself is not graded, so students caught plagiarizing tend to shrug it off with "It's just a draft. I'll fix it on the revision." This is a tricky issue. If it's early in the semester and the student has been sloppy with quotation marks or citations, I'll highlight the problem and explain that failure to revise properly will result in an F on the paper, which works. But what to do when the draft is largely copied? The slippery student insists that I can't give a 0 on an assignment that "isn't worth anything," a statement that's misguided in so many ways. 

I really need to add a line to my academic dishonesty policy specifically covering this circumstance, but the more examples I add, the more students niggle about how the rules don't apply to their particular circumstances. I'm tempted to toss out all the specifics and boil it down to one broad statement: "Don't even think about submitting someone else's work as your own or you will fail, with a capital F and a letter to the provost." But I can imagine the excuses: "I wasn't thinking about cheating; it just happened. I have a different learning style, see, that makes words just fall onto the paper without ever passing through my thoughts. It's not my fault!"

And if that's the case, it's not my fault if a big fat 0 accidentally falls into the gradebook.