If you want to go legal, by all means do that. But why not ask for "good drives with no odd noises which also pass the drive maker's diagnostics"?

To go legal you would craft a boilerplate that includes how you accept drives for payment. That is you define that you'll perform an audio check for bad bearings, clickers (which is a well accepted term for a certain failure mode) and proceed to how you conduct the maker's diagnostics. To make it all legal you don't pay for failed drives and will return failed hardware at your expense.

Bob