California’s wine country has seen a rash of thefts of solar panels from vineyards recently, giving rise to a mini-industry of vineyard security systems . It makes sense. Thefts of scrap metal—the usual market for rural thieves—are way down thanks to falling prices. And solar panels are proliferating in vineyards, usually installed in remote (but easily accessible) locations. There is another factor at work: Wine is legal, but marijuana...