Costco is known for having such a lenient return policy that people try to push what they can get away with.
Aside from a few specific exceptions, the big box store will let you return just about anything if you're not completely satisfied—including your membership.
Sometimes, they don't even need your receipt to process the return; instead, they can look up purchases from your membership card.
People have returned a litany of used, broken, and half-eaten merchandise...