When some friends and I visited the Amazon Go store in Seattle, we tried multiple different ways to fool the cameras, such as putting the bag over the item on the shelf, or picking it up from the shelf, placing it back on the wrong aisle, and then another person picking it up. We mentioned it openly to the employees. Employees in the store couldn't care less, they were just busy restocking and making the aisles look organized. There must have been human review of our movements on camera though, because my friends who didn't mess around got their receipts immediately when they left the shop whereas mine took half an hour to arrive.