I agree the AD used these classes specifically to keep otherwise ineligible "students" eligible. But, every college has easy classes and the students who want to find those classes, or instructors, will find them, tell there friends and every semester people will flock to them. Now, none of these will pass people for a single paper written by someone else, or not require any contact with the staff. So, UNC's goose is pretty much cooked in that respect, but the existence of easy classes in of itself isn't that uncommon. I've seen classes where attendance and multiple choice tests comprise the grade, others where a single project is the basis for the grade. You can also rack up elective credits though short session classes, even classes that meet only once or twice. It's also not unusual for athletes to cluster into the same classes. One, they are not there primarily for their education, UNC doesn't have a monopoly on that. Second, there are very real scheduling issues when you are on an athletic team.
I had one independent study course, that the dept allowed me to substitute for a class that everyone, and I mean everyone, hated. The IS syllabus? Design a modification for a piece of testing equipment that the school used for outside paid consulting work. At the end of the day, it was some research, a few meetings, a brief write up and couple of drawings that I handed off to next guys who eventually built and tested the thing. If I'm an athlete, is that special treatment? Or is it an astute understanding of the student handbook?