The number one rule, for orchestras, is to wear black for concerts (except for men - a white dress shirt is accepted). The dress, the vest, the pair of shoes; everything has to be black.

So, when A shows up a few hours before a concert wearing her deepest black, nobody thinks much of it. But when it is time for the concert makeup application in the bathrooms, B notices something that stands out: A's eyeliner, eyeshadow and nails are also tinted black, and that is something unusual.