I suspect that a great many people who buy high end knives don't actually use them for anything, and thus, they sit in their sheaths for years at a time in a drawer somewhere. The coatings help there. Plus it may simply be a status symbol, as many high end knife makers coat their blades. Some of them are for "tactical" reasons which I won't bother to sneer at here. And finally, as in Scrapyard's case, the coating may simply be to hide imperfections in the steel as-forged.

All of which reasons are aimed at the presentability of the knife and not its field performance. I've had my Dogfather get a little bit of rust started after whacking through brush for a while and then putting it away for a day or two. When I pulled it out again, it was a matter of "Oh, hey, rust" and wipe the blade on my pant leg. No more rust. Move on.

Finally, if people are really freaked out about the potential of their knives rusting, try treating them with some spray-on furniture wax. Problem solved (for a while).

I have to agree with him as far as functionality: rust is not an issue on carbon steel tools under normal, active use conditions. Rust only becomes a significant problem when it goes unnoticed for significant lengths of time. Otherwise it just wipes off casually.