Sales is an interesting occupation. At Costco our members (customers), see us in our red vests and ask the location of various things. Or they have particular questions about computers or televisions. Sometimes they just need someone to load a safe onto a cart.
We emphasize customer service, even if there are only a few of us on the floor.
So when a members starts a conversation with: "A while ago you had a..." I have a sense of dread. Usually this item is something we do not have and may, or may not have in the future. I can check the item and see if there are any in stock, at the warehouse etc. This only provides me a two week window on any given item. If you see something at Costco and you want it... buy it. Because, it may not be there the next visit.
Answering the "why do you not have something" is a slippery slope. Luckily, we have many long time Costco employees who have honed a response with experience. So I listen dutifully when one of these explanations, are spoken from a knowledgeable one. The corporate philosophy is to be honest and forthright. Which works well for me. I have never had management tell me not to tell a member something honest. However, presentation in these situations is key.