The success of Costco’s enterprise mannequin depends on rigor. The wholesale retailer, which makes use of a membership system, strictly displays entrances and exits and double checks buyer receipts.

But for associates and kin of members, there was a widely known hack for scoring Costco’s low costs with out paying an annual price: the self-checkout lanes. Some customers discovered they may borrow a member’s card, or a member’s QR code from the Costco app, and keep away from the identification necessities of the common checkout lanes.

That workaround is coming to an finish. The firm stated in an emailed assertion on Wednesday that it had seen that nonmember customers had been utilizing different folks’s membership playing cards, which in accordance with Costco coverage are nontransferable, within the self-checkout lanes.

“We are now asking to see their membership card with their photo at our self-service checkout registers,” the corporate defined, including, “If their membership card does not have a photo, then we ask for a photo ID.”

Costco is beloved by customers for its $1.50 scorching dog-and-soda combo, towering rows of inexpensive bulk goods and its signature Kirkland model merchandise — all the pieces from linens to liquor. An everyday membership prices $60 a yr, and an government card prices $120 a yr.

Katie Thomas, who leads the Kearney Consumer Institute, a administration consulting agency, stated it was a “not unreasonable hack” for infrequent customers to borrow a pal’s Costco card or QR code, including that she thought it might result in new paid memberships. Ms. Thomas stated she herself was lately scolded at a Costco for utilizing her mom’s membership card, although she stated she was additionally a member.

Costco stated in its assertion that it was “able to keep our prices as low as possible because our membership fees help offset our operational expenses, making our membership fee and structure important to us.”

The retail market has grown tighter, stated Neil Saunders, managing director on the retail consulting agency GlobalData, who guessed that causes for the crackdown at Costco would possibly embrace growing pressures on company margins and the rising price of commodities, labor and overhead for wholesalers.

“They probably turned a blind eye to it whilst growth and everything was looking rosy,” he stated, however have gotten stricter in a tougher financial surroundings.

Though Costco confronted provide constraints and labor shortages in the course of the pandemic, it reported strong operating results for 2022 in an annual report that additionally boasted about new gadgets, together with “BBQ pellets, women’s jeans, reformulated dog food, sauté pans, fresh mini cakes and chicken yakisoba.”

The firm additionally reported that it had practically 119 million cardholders final yr. Revenue from these membership charges totaled $4.2 billion in 2022, up 9 % from 2021. Costco’s web earnings was $5.8 billion final yr, the corporate reported, up from $5 billion in 2021.

“You see the importance of the membership model,” Mr. Saunders stated.

The member renewal fee was round 90 % worldwide in 2022, the corporate stated. Costco has not raised the price of its membership since 2017, however executives indicated in a latest earnings name that the associated fee would possibly improve.

Ms. Thomas identified the clear parallel to Netflix, which announced last month that it could start kicking folks off the service in the event that they had been utilizing somebody’s account for greater than 30 days whereas at a distinct location, attributing its crackdown to shifting financial forces and elevated competitors.

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