Marketing. You, the consumer, are known to purchase more willingly from an organized shelf than a messy one. They can't staff enough to provide the attention necessary to keep the coolers tidy and are going to find out how much you opening the door influences your final purchase decision. Have you invested enough into the action that a disarray of product no longer holds a negative value? Because money was invested, I'm inclined to believe they already did a study and found it to be a financial positive.