Retailers who are currently or even thinking of implementing electronic payment options for shoppers via their mobile devices may want to take a moment and learn a lesson from Starbucks' recent mistake. In an article for Computer Weekly, Caroline Baldwin recounts her disappointing experience with Starbucks' mobile wallet offering, My Starbucks Reward. The app works by rewarding customers with a star every time they purchase a drink via the technology. With 15 stars, the shopper gets a free drink. However, when Baldwin acquired her fifteenth star, she was told she would receive a coupon in the mail over the next four to six weeks for her free drink. Baldwin writes that she doesn't understand why she can't redeem it through the same barcode system and why the information isn't featured on her account. The incident prompted Baldwin to reflect on mobile payment campaigns and make a few suggestions, including allowing customers to redeem offers and rewards using their mobile devices. Businesses considering implementing mobile payment apps should always make sure to test them and keep consumer convenience at the heart of development and investment.