I don't know anything about the UNC program, but their grading structure, as described, is not that different from many other top schools.
The visits part is different though. I remember reading an interview with the Wharton director of admissions, and he was clearly against any factors that might be influenced largely by money. For example, visits were not used as an indication of interest because rich folks obviously can visit lots of schools without thinking about it, while it might be a burden for poor folks to visit even a single school. I believe this is a fair attitude, but then again, Wharton probably doesn't need to worry about application volume and yield as much as UNC.
Schools that are traditionally used as back-ups are particularly sensitive to personal visits (NYU, Berkeley, Darden and even Kellogg) and well-defined interest in their programs.
(Note, I'm just generalizing with rich/poor. It's a burden for average folks to take time off work and spend money flying around to visit as well).