Amazon’s $13.7 billion purchase of Whole Foods, announced Friday, will greatly accelerate what had been careful steps by the e-commerce giant into the world of brick-and-mortar retail.

But a patent dated May 30 details a possible plan for stopping customers from doing in its own stores what Amazon itself has been helping them do everywhere else for years: find better prices for the same products online.

The patent, which has been written about in Bezos’ own Washington Post, details a method for blocking, redirecting, or otherwise controlling customers’ attempts to comparison shop on their smartphones when using a store’s Wi-Fi network. The system would identify when a customer is trying to access a competitor’s website and take action. According to the patent description, it could block the action outright, redirect it to the retailer’s own website, or distract the customer with a coupon or a salesperson’s attention.