Costco is cracking down on membership sharing. The store is checking membership cards, so if you lend it out you may want to rethink it. The policy got lax during COVID, but now Costco is making sure that only members make purchases. Even if you bring a friend with you and they buy the stuff after you scan your membership card it’s a no-no. Expect more questions from employees and plenty of verification checks when you shop there and don’t take offense. Costco has a very slim profit margin, so they make their money on memberships.