Why do I need to send back a piece of the broken lock as part of my claim?

ONLY FOR REGISTRATIONS PRIOR TO JUNE 21, 2016:

A piece of the lock serves as proof of lock failure. It is also proof that the bike was locked properly and that the lock was in use.

In addition, as part of our ongoing improvement process, our engineering team inspects every lock that is sent to Kryptonite. We value this information a great deal.