I recently made some gift card and event ticket purchases (4 orders total) through Costco.com and one of my orders got delayed. I eventually got a phone call from someone at Costco who said that they noticed that I hadn't bought anything online in the past year and then all of a sudden made a bunch of purchases. They wanted to make sure it was actually me, and once I confirmed that it was I got my email with the gift card right away. So it may be mostly automated but I think they can also be flagged for manual review and verification.