India, Jan. 11 -- A year or two ago, Sam's Club (the warehouse stores that are part of the Walmart company) offered customers a new app called "Scan and Go." The company set up folding table stations inside the stores staffed by store representatives to tell customers about the app and how it worked and to give out pamphlets.

In case you aren't familiar with it, the idea is this -- you download the app, open it on your phone, and login with your membership ID. As you put items in your cart in the store, you use the app to scan the barcodes with your phone. When you are done, you skip the checkout lines and go straight for the exit, because you have already checked out and paid on the app. The door staff checks a QR code on your phone at ...