Anything with iron can rust, including stainless steel.

Stainless that gets scratched will rust, as well as if the mild steel (or whatever the dust is,) causes a galvanic reaction. Or any where that the stainless is exposed to lesser steel. (Which is why you can’t store stainless with mild.)(including, in point of fact to milde steel dust…)

Alternatively, exposure to corrosives- bug juice, road salt and other deicers, potentially a dozen kinds of automotive fluids.

There’s a reason the rest of the automotive industry doesn’t use exposed stainless anywhere. And that reason me is it rusts (and is difficult to work with, and is more likely to kill people in an impact.)(people at Tesla told musk this. He didn’t care. Musk is an idiot.)

A wired as a source talking about the issues in CA drivers (where there is a lot of salt in the air.)