"Basically, you've got to dress to impress. Don't show up in your dirty knickers and your flip-flops. You should be wearing your finest: black tie if possible."Obviously, Mr. Yauch has never attended a festival as a concert-goer. At a festival, a concert-goer's main needs and concerns are comfortable shoes (such as flip-flops), sunscreen, food and water -- not formal wear.
By the time the Beastie Boys take the stage at the Sasquatch Music Festival, I guarantee our knickers will be dirty (or possibly lost) and our flip-flops full of grass and dirt (or possibly lost).