I do not at all doubt that if you are an "urban" looking black person wandering around a suburb like Kenilworth you are likely to be harassed by the police. There are Chicago suburbs that are somewhat defined by whiteness.
But even the whitest neighborhoods in Chicago have pretty significant African-American or Hispanic populations as well (there aren't that many black families living in Lakeview, for instance, but there's a large number of Hispanic families there).
Also, no cop has ever warned me to get out of a dangerous neighborhood in Chicago. Has that happened to you? Where were you?
Though now that I think of it, maybe it was both.
And thinking about the other thing, I don't think I have ever seen a potential "just for being black" stop anywhere south of Belmont, either. So I guess that can't be pinned on CPD. Maybe the commercial centers in Rosemont, near O'Hare? Not sure if that's in the official city limits or not.
It is worthwhile to note that you might be black and "out of place" in your own neighborhood if you are outside in your own yard with a camera recording while the police are doing something.
You can compare maps at http://gis.chicagopolice.org/clearmap_crime_sums/startpage.h... and http://www.wbez.org/series/race-out-loud/where-we-are-mappin...
If you're black or Hispanic and in the wrong place, the police will approach you and try to find any reason. Any reason to what? Any reason to anything, that's what.
The racial segregation in Chicago is no longer enforced by real estate agents, redlining, and covenants. You can rent wherever you like in the city. But how often do you want to be forced to talk to a cop when you step outside?