Loïc Gouzer doesn’t think the art world understands Banksy . In fact, he thinks it’s scared of him. On May 20, Gouzer’s auction platform Fair Warning will sell  Girl and Balloon on Found Landscape , a painting from Banksy’s “Crude Oils”   series, in an invitation-only live auction staged inside Tiffany & Co.’s Fifth Avenue flagship. The work, which modifies a thrifted landscape painting with the artist’s signature red, heart-shaped balloon drifting away from a young girl, carries a $13 to $18 million estimate and will be on view to the public in the store ahead of the sale.  Related Articles For Gouzer, the setting is part stunt, part argument. A street artist in a luxury temple. A controlled, almost private sale wrapped in spectacle. And, as he freely admits, a bit of fun. But the real point is Banksy himself. “I think he’s the most consequential artist of our time,” Gouzer said.…