In early March, Mark Hoppus, the singer and bassist for the long-running pop-punk trio Blink-182, and his wife, Skye, were special guests at a Sotheby’s modern and contemporary art auction in London. The sale featured a piece from their collection, a rare Banksy titled “Crude Oil (Vettriano),” up alongside works by Yoshitomo Nara, Gerhard Richter and Vincent van Gogh.