Just a thought from a former retailer. Thermal receipts fade fairly quickly. Use a Sharpie to write on the back the date, register#, cashier's name or number, transaction #, item # and price. Then you have the original even if faded. Most thermal receipt paper has a company logo on the back. With the computerized inventory systems it is easy to check stock to see if a store has on the peg or shelf what it is supposed to have. One of the last bogus returns I was involved with was a lady trying to return an expensive dog grooming kit, a digital fuel meter and a blingy ladies western belt. Each iten was $50-60. No receipt and she said her boyfriend bought them yesterday but lost the receipt. I checked stock with a scanner and was short one of each on the shelf. Needless to say, no refund was given. I had the items in a basket and told her that I would hold the items until she could find the receipt. No argument from her and never saw her again. Had it been a customer I knew or one of my employees knew the outcome may have been different. BTW, I did get a nasty phone call from the boyfriend but nothing came of it.