Originally Posted by HillRider

Often the manufacturer wants the defective item back so they can see how it failed. It isn't always a matter of distrust. Perhaps Panaracer had a raft of these failures and already knew about the problem.

Bell Sports used to send you a replacement helmet for $20 if you damaged one of their helmets in a crash and sent the dead body back to them. They wanted to see how it was damaged and use that info to make them better.