can't a good painting job and regular cleaning prevent rusting?
They are good enough paintjob. Some companies use cheap mesh quality but 1 can't expect a lot on a case that costs less- or cases that give a lot of headroom of space, some features and ability to do easy cable management. That's why I like 400R. Even though the I/O section and the vent section on a base is weak, you're getting pretty good stuff for the case. That L shaped section is half inch depth more mind you- and that does help a lot.
Well if you're living in a place with humid climate and lot of pollution, it can slow down the process. If you see some I/O connectors, some are made by foxconn whereas others are made by another company- like LOTES. I see the metal housing over these connectors fading away and eventually rusting, whereas the other one doesn't. If its used in another condition, it lasts longer- perhaps not even rusting at all.
btw even a corrosion after a year hurts too much you know because you spend 5-8k for a case and it loses its face within a year.ahh but i can relax as i have 2 years warranty and hope corsair will provide replacement for rusting.
That needs to be cleared with the manufacturers na. When questions were asked to few manufacturers, they didn't really give a straight answer if rusting is covered or not. They may entertain few complaints but unless one says rusting is covered under warranty than there's not much can be done. Companies have their own forums. People need to start asking manufacturers directly, especially when companies have twitter, facebook and their own forums. If people don't ask them directly then they won't know. Nothing happens if a small group of 1-4 people say it. People need to ask.