India, Feb. 11 -- Shelf-mounted cameras paired with artificial intelligence facial recognition software that can identify a person's age, gender, and ethnicity were one of the emerging systems being pitched to retail companies during this year's National Retail Federation Big Show in New York in January.

The idea was to give physical stores demographic information that could guide how they market to individual customers. It's something that could give them a competitive edge against online retailers such as Amazon, that have been leveraging customer data all along.

But using cameras to capture photos of your customers in a way they may not even notice seems like it could be crossing that line between cool technology and creepy technolog...