Sooo if you had an object with a simple mechanical part that worked ok when you were using it, then you dismantled it and stored it around the house, then you listed it and it sold and you waved it goodbye, then the buyer contacted to say the simple mechanical bit did not work.......
You would have to refund wouldn't you?
Because that doubt is there if it was stored something might have happened to it [although you can't imagine what].
Or would you be brave and examine it carefully when it came back to see if it had an obvious break.....but even so would you have a leg to stand on.....?
Hmmmm?