Next time you head to Costco, make sure you have your plastic or digital membership card – and a matching ID. The members-only warehouse retailer is really starting to crack down on non-members.

If you usually borrow someone else's Costco card, soon you won't be able to use it unless they head to the store with you. Costco is going to be cracking down on membership sharing. They're going to ...

In an effort to crack down on shared memberships and prevent nonmembers from sneaking in, Costco is installing card scanners at the entrances of its warehouses, the company announced on its website.