Thankfully not as expensive but...
I parked up at a friends a couple of weeks ago. Lovely wooded drive, a nice day, so left the sunroof open (car was never more than 20ft away, in full view, locked) for the half hour I was there for my cuppa and biscuit.
It didn't rain, no birds scored a lucky hit, and no sun drenched idiots threw anything in.
I was alarmed to find the exterior and interior covered of tiny bits of colourful foliage. Back seats, front seats, carpets, dash. Everywhere. My friend called them 'catkins', and found it very amusing. I don't know what they were, but gather they came from the tree under which I'd parked.
Missed my hour's pub-pass hoovering it all out