If I understand correctly (and I hope I do with a degree in chemistry), it’s moreso the long periods of exposure to wet environments. If those environments also include frequent exposure to salt it expediates the transfer of electrons to the outer surface of the stainless steel and causes oxidation.

Oxidation/rust/petina isn’t a bad thing. A thin outer layer of rust is sometimes used as an aesthetic preservative in architecture though. There are buildings that have heavy surface rust on them intentionally.

Probably not what you’d expect or desire on a vehicle, but very much possible. I wonder how the DeLorean DMC-12 held up in nasty conditions?