My highschool was one of middle class whites (60%) & ghetto blacks, who were bussed in (40%). Only a handful of the bussed in kids went to school to learn, and those kids had something in common- a parent who cared. There was a small minority of middle class blacks also & they performed at the same level as whites from their economic status.
Regarding the double standard. In my school it was the exact opposite of what you describe. The black kids were simply predators who would terrorize the white kids. When these kids would beat the hell out of a white kid, who just happened to be in the bathroom at the wrong time, the white kid would get suspended for the same amount of time. This happened all of the time & parents could do nothing about it. Why? Well the school didn't want to look racist. I know! There wasn't a white kid in my school who wasn't afraid everytime the bell rang. MAFREE, I lived it & know. The double standards are 100% opposite then the one you describe.