Costco is the latest company to discourage its customers from sharing their memberships with outsiders, with employees checking shoppers’ IDs more frequently to ensure they’re not freeloading off a friend.

“Since expanding our self-service checkout, we’ve noticed that nonmember shoppers have been using membership cards that do not belong to them,” the company said in a statement to Fortune. “We don’t feel it’s right that nonmembers receive the same benefits and pricing as our members.”

The crackdown comes as more shoppers use self-checkout at the stores. Employees are asking for IDs at those registers as well.

It also comes as people grow more and more concerned about the cost of groceries, increasing the appeal of bulk buying. Costco, though, charges a $60 annual membership fee to shop at its stores. That price has been the same since 2017, and many people have wondered when the company will increase it.

So far it has resisted, but in March CFO Richard Galanti told investors “it’s a question of when, not if.”

Earlier this year, Costco boasted 123 million cardholders and a worldwide membership renewal rate of 92.6%.

The Costco crackdown follows a similar ban on password sharing by Netflix. While unpopular with subscribers, that action has been a net positive for the streaming service. Data from third-party analyst Antenna shows there has been a big surge in new user sign-ups since May 23, when Netflix said it would begin curbing the long-accepted practice. Nearly 100,000 people signed up for accounts on both May 26 and May 27, Antenna said.