Previously on the NonSequitur, I'd reconstructed the core arguments of Steve Gimbel's innovative and rhetorically powerful "Open Letter to Students." Overall, there are three arguments not to plagiarize: (1) the moral argument: it's theft, it's lying; (2) the practical argument: it's a bad gamble; and (3) the argument from fidelity: in plagiarizing, the student breaks a bond of trust with the teacher (and one the teacher has upheld).
The trouble is that arguments from fidelity are considered fallacy forms. They may either be a sub-class of arguments from pity or at least they are considered in the same family as arguments from pity and the other emotive-expressive argument forms that generally fail relevance tests. (E.g., arguments from outrage, wishful thinking, arguments from envy, etc.) Additionally, arguments from fidelity also work on a person's self-identification as a member of some group or other, and so they rely on the similar forms of reasoning as ad populum arguments. The rough class of affections these arguments key on are: the desire to belong, the desire to see oneself as loyal and constant, the desire to be proud of one's ties. Some examples:
A1: You're a Titans fan. How could you criticize Jeff Fisher like that?
A2: Your job in this organization is to off the snitches, so you owe it to us to nail anyone who's squealing.
The trouble with both A1 and A2 are that the fidelity the person addressed by them has to these organizations underdetermines what that person's supposed to do. With A1, anyone familiar with the NFL knows that being a fan of a team means that you find yourself having more critical things to say about your own coach than you do about other teams' coaches. A2 works on loyalty a little differently, as here deviating would be breaking the bond with the organization. But that is the right thing to do (the problem, of course is that someone will fill your position and likely come to murder you, but that's a different issue). The point is that A1 and A2 show two different ways that arguments from loyalty can fail. Here's a basic schema for the arguments:
P1: You are a member of X
P2: If you are a member of X, you have an obligation do A (as an expression of your loyal membership in X)
Therefore, you should do A
The problem with A1 is that P2 is false in its case. The problem with A2 is that even though P2 is true, the obligation to A does not trump the moral reasons not to A (in this case, A=murder). So the conclusion does not follow.
Back to Gimbel's argument. Here's the reconstruction:
P1: You (student) are a member of this student-teacher relationship.
P2: If you are a (student) member of this relationship, you have an obligation to turn in non-plagiarized work. (or: refrain from plagiarizing…)
C; Therefore, you should not plagiarize. Plagairizing is a failure of loyalty to this relationship.
Two ways arguments from fidelity can fail are, I think, in A1 and A2 fashion. I think Steve's argument passes these tests. It passes the A1 test, because P2 is true in Steve's case. Syllabi, honor codes, and things like that make it so it's clear what a student's role is. It passes the A2 test, because there are no moral reasons that trump the transmission of obligations of group membership to what one ought to do. In fact, because of the moral argument against plagiarizing, the support for the conclusion is strengthened, not weakened (as with A2).
Arguments from loyalty place a prima facie obligation on others, and we can recognize those obligations in the shame we'd feel were we not to live up to those obligations. That's what make these emotional arguments. But their emotionality need not make them fallacious. They are fallacies when they either proceed from false presumptions about what one's obligations are as a loyal X or from the thougth that even if one has prima facie obligations to X to do A, they are always ultima facie oblligations to do A. In Gimbel's case, he's made neither error. His case, then, aggregative. The moral, practical, and fiduciary arguments converge on the same conclusion.