Without a code of conduct, schools will not know whether they are participating in labor exploitation. And without a strong code, promises made about good labor conduct can be easily broken. Fighting sweatshops and child labor is tricky business, for everyone involved. It is too easy to say you are clean and to then find out that you are not. Campus codes of conduct must not succumb to the plausibility of denial.
Schools care a lot about their reputations, just as do personalities, and politicians.
For many of us, it is all we really have. So it will be in schools' best interests to make sure their codes are strong enough to get the job done. Because if you think that the publicity is bad when you are found to participate in labor exploitation, wait until it is discovered that you participate in labor exploitation after publicly declaring yourself against such practices. You will then know how cold and unforgiving the world can truly be. But the other reason Duke cited was that it was simply the right thing to do.