DAYTON, Ohio (WDTN) — Costco is known for checking your membership card at the door, but now the big box store might also ask you to prove you are really you.

Costco said its membership policy has not changed, but more non-member shoppers are using cards that they didn’t pay for.

“Our membership policy states that our membership cards are not transferable and since expanding our self-service checkout, we’ve noticed that non-member shoppers have been using membership cards that do not belong to them,” company officials said in a statement sent to Nexstar.

The company routinely asks for the membership card at checkout, but now, officials say staff will ask for proof of identity at the self-service line. That means asking for photo ID if your membership card does not include a picture.

“We don’t feel it’s right that nonmembers receive the same benefits and pricing as our members,” Costco staff wrote.

Costco says the membership fees are essential to their business model, helping offset operational expenses.

The wholesale chain has not raised fees since 2017, but the company’s CEO recently said on an earnings call that a Costco membership fee hike is likely coming at some point soon.