It's good protection for their other customers. Just becaue the item looks unused with tags still attached etc, doesn't mean it's still in brand new, pristine condition. I'd rather buy from a retailer knowing the item i was buying hadn't been bought already and taken to someone else's house, sat about for a while whilst they decide they don't like it, and returned to the shop. Anything could have happened to the items whilst it was away from the store - new leather trousers sat about it wearing no underwear, gloves put on after picking nose/arse/worse, item been in a smokey house and stinks of smoke, or malicious actions such as stitching being unpicked, or sharp objects inserted into the armour.. Credit note is the best option to avoid the nasties and ensure new products are actually new.