I keep seeing "Why were you shopping at 10am". Because the store opens at 10am. Any later and the parking lot is ridiculous (even handicap is full) and the store is packed with massive line-ups. Her dad probably always shops during the week right at open (like I do) to make the trip a 30 minute endeavor rather than 1hour and 30 minutes. Given his mobility issues the time of day makes sense. Someone else pointed out she probably had this day off as a stat. So he picked the one week day his daughter could go on an outing with him.

I have worked a lot of retail jobs. Exceptions can be made and usually lead to much happier outcomes for everyone with very little effort. I've been to Costco (my membership) and my friend has paid using her card (non-member) while with me. Never had this issue brought up, did not even know it was wrong, so her dad probably didn't even know. A request to plan better next time and let the lady buy this time would have worked and is possible.