If you live in Seattle and want to pick up a quick snack without having to wait in a checkout line, you've now got two options for where you can do so. On Monday, Amazon officially opened its second cashier-less convenience store in the Emerald City. To begin a shopping experience at an Amazon Go location, a customer must first download the Amazon Go app and swipe it upon entering the store. Then, cameras and sensors constantly monitor the items the customer removes from the shelves. When the customer later walks out of the store, Amazon charges their account for the items they take with them.