Grand Theft Auto V—the year's most anticipated, and most controversial, video game—is such a huge hit it "could be a nontrivial contributor to the U.S. gross domestic product." But it's a huge hit in part because parents are buying it for kids too young to understand—as one video-game clerk explains.

Sigh. Rohan Dawkins, 21, of Delray Beach, Florida went to a GameStop store on Tuesday to pick up his copy of Grand Theft Auto V. Dawkins, who attends a special needs transitional program for adults during the week, had been saving money from his weekend job at Home Depot to purchase the game. Over the past several weeks, he’d been regularly stopping by the store to pay for it in $10 to $20 installments.