I didn't even realize it until I went to unlock the case at the end of the work day. The key broke inside the lock and all I had on my keychain was the end of the key. No, it didn't work when I tried to stick it in the lock and turn. Had to strap my backpack AND my computer case on my back.
When I got home, I took the case frame off the Enertia and then, with a screwdriver, was able to open the lock. I took the lock off of the case (easy - just a C-spring holding it on) and could see the key inside the cylinder.
The key would not budge.
I ended up finding the part number for two new cylinders and 4 matching keys online (Z227) and I ordered it from TwistedThrottle.com. It was about $25 with shipping.
http://www.twistedthrottle.com/givi-2-case-lock-set-with-4-matched-keys-z227The keys are cast brass and subject to metal fatigue, as my internet research pulled up lots of hits for Givi Broken Key on many forums. Until I get the keys and cylinders, I'll manage, either without side cases (naked!) or with bungie cords (classy).
Just a heads up: inspect your keys if you have Givi cases on your bikes.