Depends where you live... this "fashion statement" has hit big in the NorthEast portion of the country and everyone under the age of 18, regardless of skin color is doing it. It's not a racial divide, it is like most of the other things talked about in this thread, a chance to differentiate from the normal. I personally think it looks stupid, "even on Chad Cordero"
I think more importantly than worrying about who is doing it (from a race or class perspective) is the fact that most people including myself just choose not to ignore it. If ignored it would probably go away...