Anecdotally I see the cops talking to white youth in "gangbanger" dress quite often. I'm not sure the lesson is anything other than "if you don't want to be treated like a criminal, don't dress like a stereotypical example."
I personally have not seen white youth in gangbanger attire accosted by cops in white upper class neighborhoods. I have seen blacks accosted in upper white neighborhoods. I’m willing to bet that most interactions between cops and whites in gangbanger attire in white neighborhoods are much less intense than between cops and blacks in said attire in white neighborhoods.