Their pharmacy is available to the public, I know. Got our Novavax vaccinations there twice, just had to let the door person know where we were going.
Take it for what it’s worth, I had forgotten my card at home one time when I went to Costco for a servicing of my hearing aids, and they waved me through but told me that I couldn’t buy anything other than hearing aid batteries, which you pay for at the HA kiosk. Basically, nothing could be scanned at the front cash registers.