Cards are not physically mailed. KOA campgrounds do not require a card in hand and can look you up during check-in. Should you want a card there are several convenient options available.
That doesn't mean this area has to always be empty. When you start reviewing camping options, your history will display here to help compare sites and find the best stay. You will be able to share your stay information with friends or family and save it for a later time if you have a KOA.com Account.