Hip-hop genres flare up and become passé in the blink of an eye, but no style ever truly dies in New Orleans.

Late last year, six people were arrested in New Orleans for tagging the graffiti message “Free Lil Wayne” in the French Quarter. It was an odd message of support given that Lil Wayne hasn’t lived in New Orleans since well before Katrina and had yet to start serving his sentence in New York City, where he was convicted of possessing an unlicensed gun. Why t...