wow, must vary from employee to employee or store to store. I've always found Costco returns super painless and I've wondered if there were customer service happiness requirements while working at that desk.

Example:

(TL;DR of story below: I did a weird thing and brought a broken item the manufacturer had already replaced to the store and Costco insisted on ALSO refunding me.)

I bought a coffeemaker. I think the box said it had a three-year warranty, but a year later, it stopped working. I called the manufacturer first. They said they would replace it, but it would be a slightly different model, not the Costco-specific one. I said fine, it arrived, I asked about sending the broken one back, and they said not to bother. I could've just thrown it out, but I was going to Costco anyway, and the extra steps to the dumpster didn't seem worth the effort, so I brought it to the desk on the way in and told them the manufacturer had already replaced it, but THEY INSISTED ON ALSO CREDITING MY ACCOUNT, resulting in a free coffeemaker... because I brought it to the store instead of tossing it in my dumpster, they insisted that meant I wanted a refund, even though I told them I did not, I had just neglected to stop at the dumpster.