When I was in math grad school a young woman from an HBCU was admitted to the program. The graduate adviser placed her in courses appropriate to what her transcript indicated. We took her into our study groups and it wasn't long at all before it became clear she was not sufficiently prepared. As an attempt to salvage the situation the graduate adviser moved her into a slate of courses a tier down from where she started out. I don't recall if she stayed through the full year after that.
This kind of thing screws two people over, the one who got in and the one who should have gotten in.
