We need to make signs with this on it. The PC world is complaining about Mark Cuban's comments but he is absolutely correct. Appearances and first impressions mean something. If you want to be perceived as a gang banger then dress and act like one. Just don't complain when people shun you.
Several years ago, several of us were walking back to the office after a group lunch. Ahead of us was a group of tough black youths hanging out in front of a barber shop. Joe, the only black guy in our group, told us to cross the street. "What's that matter? Aren't those your people?", we jokingly asked him. "They are not MY people." was his response.
There is nothing wrong with crossing the street to avoid a perceived threat. At the worst, the individual may get his feelings hurt, but if you are wrong about him, you could get killed. In engineering terms, we call that a low probability, high consequence event. The down side is so bad that you take the precaution anyway.