Rust? Yeah, it rusts. Has it rusted away to nothing? No. Has any of the rust that I have gotten on my knife taken away from its abilties? No. Its carbon steel. Carbon steel rusts, and the only way to keep it from doing that is to coat it with something.
Doesn't matter what you put on it, paint, epoxy, patina, whatever, if you use it, it will wear the protective coating off. Think about it like this, what part of a knife is important? The edge. Anyone here ever seen an edge rust over? Of course, you sharpen it, it goes away, no different than the body of the blade.
I like carbon steel more than stainless, and I like my blades uncoated. I have never had a knife rust away to nothingness or even to the point that I thought it needed attention. I was backcountry for 9 days once (heaven) and my BK2 never rusted to the point that I thought it needed more than a good wipe on ma britches (Hillbilly for pants). Did it rust? Yep, I basically live in a rainforest, in the summer humidity will stay at 100% for weeks. Never had that orange flaky rust, but I am a user not a knife storer. When it rusts, I hit it with some 0000 steel wool and mineral oil, or just mineral oil. Either way, my knives stand a better chance of me breaking them, rather than rusting away to nothing.
I don't worry about rust or a stain on my blade, no more than I worry about a sunburn on my skin.
I hope this helps.
Moose