It happens all the time in stores that display the Gift Cards in a location that is available to the public. Retailers know about it. People will come in and grab a stack of gift cards off the rack, then remove the grey sticker and write down the code. They can purchase those same grey stickers from Amazon and place them over the code again. After they return the cards to the rack, they just need to wait for you to activate it through the check stand and can spend the money before you get a chance to. These same retailers will lock up products in their store when they are concerned about theft that cost them money, but have no problem when their customers lose money through this gift card scam. I would first go back to the store and complain to management and corporate offices as they are the only ones that can change how they market the Gift Cards. In the future, only purchase Gift Cards that are sold behind a counter and are not accessible to the public.