Step 1: Mount the City Case without using the key to lock the catch that holds it to the bottom of it's mounting rack.
Step 2: Ride over some crappy pavement like this at 65 MPH:
(http://i82.photobucket.com/albums/j246/smithduck/crappy_pavement.jpg)
Fortunately, I didn't realize it was gone until I pulled over to take a pic 30 miles later so I was spared the emotional trauma of witnessing it's high speed highway death in my mirrors. (I'm sure that it must have been spectacular though.)
When I returned to the crime scene (suicide is against the law) all that remained was this:
(http://i82.photobucket.com/albums/j246/smithduck/city_case_remnants.jpg)
By the time I got back somebody had absconded with the other half and it's contents. I'm OK with that though as IMO stuff that flies off of vehicles is fair game. Like this most awesome Phillips screwdriver that I found while scouring the ditch for body parts of said deceased City Case:
(http://i82.photobucket.com/albums/j246/smithduck/screwdriver.jpg)
And losing what was in there is inconsequential to me. (Some dirty underwear and a copy of Obama's Kenyan birth certificate that I was planning to mail to Donald Trump.)
I am not overly traumatized by this event as I have three other sets of City Cases and this one was from the most worn set. I've got something like a couple of hundred thousand miles on various K bikes I've owned and this is the first time a case has ever committed suicide on me. I guess I'll be locking them with the key from now on.
Most importantly, I laughed it off and continued with the most excellent ride that I had planned for the rest of the day: Windy Ridge to Mt. St. Helens. Yeehaw!
(http://i82.photobucket.com/albums/j246/smithduck/k75f_msh.jpg)