Costco’s 100% satisfaction guarantee return policy allows customers to return items for any reason, leading to some unusual and questionable returns. Shoppers have reported returning rotten food, half-eaten pies, and even an unopened box of frozen shrimp that had spoiled. While Costco staff generally accepts returns without question, there are limits. One employee denied a return on green and black salmon left in a customer’s trunk for months, leading to a heated confrontation. Costco reserves the right to revoke memberships of customers who abuse the return policy by returning excessive amounts of purchases.