A racist behavior used by the staff at bars, restaurants, and nightclubs with anti-urban dress code policies. The goal of "cobblestoning" is to deny service to black patrons by baiting them into a fight over their appearance (e.g. do-rag, backwards hats, bandana, baggy jeans). The origin for this term comes from a sports bar and restaurant in York, Pennsylvania called "Cobblestones" who's manager is credited with perfecting this technique.
The only back guy in our party got "cobblestoned" at our table last night after we already ordered drinks. The club manager started a fight with him about his apparel even after he offered to remove his do-rag. They were determined to find an excuse to throw him out so we all left.