As uxp describes below, this may be the mechanism Wal-Mart uses to get a price advantage, but it's not why people shop there. People shop at Wal-Mart because it's cheap. I've never known a town to have only a Wal-Mart, there are always some regional or local grocers in the game too, but Wal-Mart wins because Wal-Mart has better prices. It's nice that they use technology to gain the price advantage, but ultimately consumers don't care or know that Wal-Mart uses satellites or RFID extensively; Wal-Mart markets price, not fancy back-end warehousing.