I may have, more than once.
I had the boss's mk2n at a fair, a kid bumped me and tried to snatch the camera off my shoulder, and it dropped to the ground.
Camera was ok, the attached 16-35 broke off and rolled down the street ($400 worth of new housing/flexible printed circuits etc for the lens)
Had a mk4 unlock itself from the back of a 300f2.8 and fall to the ground, messed up all the focus points in the VF (new mirror box/pentaprism/top plate)
Had a 400f2.8 and mk4 roll off the back seat into the footwell when i braked hard
Bent the locking pin so it wouldnt retract and the camera was stuck to the lens (new lens mounts and locking pin)
Thats all i can think of now - some of the guys at work have left a bag of gear on the roof and driven away, one reversed back and ran over the bag for good measure.