Brian Renders Me Sans Clue

Qu'est-ce que c'est? Brian est sans cravate ce soir! I must admit, I do not quite understand the fashion statement BW is making this evening. He is wearing a very formal looking white shirt, black suitcoat, but a clearly visible white teeshirt and no necktie while reporting live from the Indianapolis 5oo speedway. I'm afraid I'm going to need a little hint here. It's sort of like a sandwich of generic peanut butter a la croissant served on Limoges and a paper napkin.