Well the thing that's made it hard for me to understand is that the paint is not chipped or peeled or cracked. It's literally completely gone and it's down to the bare metal. It's almost as if it was completely removed in perfect dots with no damage around each area. Normally I would think there would also be pitting and dents if it was some sort of object thrust against the car (like flying rocks or debris). I think the chemical reasoning is still the closest to explain it. Perhaps there was something on the road and when she ran it over the tires shot it out at the body of the car which explains why it's only located around the wheel. The car has never been parked on the street - it's garaged at home and in a garage at work. Weird for sure!

I actually have something similar, only smaller on me E90...

me aswell i have it on the hood of my x5! its like orange spots that is rust and when i saw this i had no idea how it got there or what happened. this is starting to be like those crop circles on our cars...