Sounds goofy to me. Aluminum would not corrode during shipping.
depends on where it is shipping from. I worked at a company that had some parts built in China and the salty sea air was pretty murderous on any exposed metal. sometimes the containers would show up dripping wet inside from humidity changes.
I do agree that it is probably rub-off from the aluminum rather than silver paint. I also worked a stretch machine for aluminum vent pipe when I was 18 and my hands/sleeves/coat/whatever I touched was that silver color after a few weeks.
aluminum doesnt hold onto paint very well even with proper prep, you can expect to touch it up pretty often.
