Costco Wholesale Club is increasing vigilance on members sharing their cards at self-checkout lines, following a rise in non-member shoppers using membership cards that don’t belong to them, reports Axios. While this is not a policy change, as memberships have always been non-transferable, the company has started asking shoppers to show their photos on membership cards at self-service checkout registers. Costco justified this measure by saying that membership fees help offset operational expenses, allowing the company to keep prices low. The company, which last increased membership fees in June 2017, is expected to raise them in the future, citing inflation as a contributing factor.