Never... (and this means ever, at all, not even for a pico-second, even if you know you will pick them up again - because you won't) put your binoculars on the roof of your car.
Always take note of the above..
It's 1981 and I had just shelled out £315.00 (tons of money then) for a pair of Zeiss B'gats. Went to Flamboro, got in the car and one mile down the road - at a junction - I was confronted with a big greasy biker banging on the car roof....."hey mate, your binoculars are on the roof".
The bins are still going strong...if very worn!
John.