Sarah's a big Star Trek: DS9 fan, but didn't recognize what the shirt was saying at first, until her mom pointed out the Klingon bat'leth symbols on the sides. The first shot, which I really love, is her laughing response to it. Thanks Anne, and thanks Sarah!
(...and for everyone who's wondering, the WWAKD? shirt is currently not being stocked in the Sheldon Store, but we may have it again for Christmas '09.)