Because optical alignment doesn't like hard knocks while some (most?) audio gear is less fussy :-)
I used to work in a hire dept. - some of the SM58's looked like they had been used to hammer nails in but they kept on keeping on.

Charles.

PS. My own audio gear rides in a medium size pelican hard case, color coded so I don't mix it up with my camera and Ki Pro kits

I'm too poor to afford to shell out on a legitimate case so my GY HD 100 sits on top of a pillow in a duffel bag. Then, I stuff two thick white bed sheets around the camera for added padding. Oddly enough I've actually used the sheets to drape over windows to darken up a scene if needed.