rowdy black tie

It doesn't mean anything. A dress code where the only demand is that there are no demands. The only criteria is that all criteria are artificial and the classic rules of fashion don't apply. Anything goes, but make it GOOD.

The fashion show will be rowdy black tie. An outfit you feel like you couldn't get away with anywhere else, you wear it here.
Rowdy black tie is a little like wearing a neon orange latex overcoat on a morning TV show.