“The practice has seen such MFA masterpieces as Monet’s ‘Grainstack,’ Van Gogh’s ‘Postman Joseph Roulin,’ and Degas’s ‘Edmondo and Therese Morbilli’ sent to fee-paying museums in Japan, to the Bellagio hotel and casino in Las Vegas, and to shows in northern Italy organized by Linea d’Ombra, a profit-making company that organizes blockbuster exhibitions.”