Chip credit cards give retailers another grievance against banks

New York

THE employee perched on a stepstool by the Trader Joe's checkout in New York City's Union Square is like an air traffic controller: Register 6 for one customer. Register 9 for the next.

The routine helps move traffic quickly through the store, where the lines can often snake around the aisles. Trader Joe's, like many retailers around the country, recently upgraded…