Another change: As soon as there are three or more people waiting in a line, the retailer deploys "line busters," employees who scan items in shoppers' carts be

Another change: As soon as there are three or more people waiting in a line, the retailer deploys "line busters," employees who scan items in shoppers' carts before they reach the cashier, says Mr. Carey, who works closely with the retailer's operations team on line speed. This isn't really news. WalMart's been doing this forever.