Costco shouldn't be this generous, even an employee said Costco's like a library

[theking]

...I saw something at Costco for the first time and thought they were way too unbelievably generous...

A customer returned a book that she bought there so I asked an employee, Costco accepts book returns?

And he said, yes because Costco is a like library where customers can just check out books and return it (sarcastically of course).. 

[DuMa]

They make enough such that they can absorb these chump change lost.  Now if everyone buys and return after reading, they might change their policy again