Have you ever wondered if you were being had when it comes to drinking wines by the glass? First, the obvious: If you are, say, drinking alone and have no intention of downing an entire bottle of Cabernet, wouldn’t it make sense to purchase that $15 glass as opposed to wasting $50 worth? You’re drinking less and spending less. Sort of. And when a friend in the hospitality industry told me wines by the glass are a racket—that the cost of the glass is in fact the cost of the bottle—I scoffed. But as Lettie Teague reveals in the Wall Street Journal, that turns out to be true. And that’s not even the half of it.