Some specialized, private, or magnet High-schools (see NRST) effectively screw over their students by dropping D's from the grading scale (i.e. A, B, C, F), thus causing some students' GPA's to come out lower than they would at a mainstream school -- unless, of course, the students refrain from receiving grades less than a C-, or 70% (or 69% in some schools).

While some students, such as I, consider this a worthy challenge, it can play hell with college farming: Grade Point Averages usually play a factor in college acceptance, and many large colleges may fail to recognize the significance of these students' lower GPA's. Then again, that usually means that college isn't really worth it, so it can all even out.