About 1978 I put my 28/3.5 EBC Fujinon in its case on top of my car, forgot it and drove off. I think the case would have protected it from the fall. I got home 20 minutes later and realized what I had done. I went back and looked and looked but couldn't find it.
I was angry at myself, of course, and vowed to never put photo equipment on my car roof again. Which I haven't. I've never forgotten how I felt when I paid to replace something I'd bought about six months before.
But it took several destroyed coffee mugs to finally learn some years back to never put anything on my car's roof.
The one that cured me was the one that slid forward off the roof and landed on the hood, when I braked at the bottom of my hill. It continued forward until it went off the front and shattered on the pavement. My neighbor saw the whole thing, and had a good laugh watching me as I picked up the pieces of my shattered pride, I mean coffee mug, and attempted to wipe coffee with too much cream in it off my windshield.