Bad news if you’re mooching off of someone else’s Costco membership: The retail giant is cracking down.

When you enter Costco, you need to show your membership card to an employee to shop. Costco membership cards are non-transferable, but the company allows members to give a second household card to one other person in their home. Anyone with a card can bring up to two guests to the club during each visit, the company stipulates.

But Costco has noticed that non-members have been sneaking in with membership cards that don’t belong to them — particularly since Costco expanded self-checkout.

Costco recently started asking for shoppers’ membership cards along with a photo ID at the self-checkout registers, the same policy as regular checkout lanes, to crack down. “We don’t feel it’s right that non-members receive the same benefits and pricing as our members,” Costco said in announcing the change.