~8 years ago, I worked at one of the largest retailers in North America (top 5). Credit card numbers were absolutely stored in logs accessible to me (an on-the-floor employee who processes returns, etc.). It was useful as I could use them to find purchases if someone lost their receipt but had the credit card. It was also incredibly insecure. I believe they've changed it since then, but it would not surprise me at all if other retailers were in the same boat.