"...the best way to keep a carbon steel knife blade from rusting is to use it frequently, giving it a wipe with a dry cloth (usually my pant leg) before putting it back in its sheath..."

Me too. I have been using knives for more years than I care to count, and own many more carbon blades than stainless. Some have a nice "patina," but I have never had a real rusting problem, even with a kitchen paring knife that sometimes gets left laying on the counter overnight wet (shame on my wife). If a thin coating of rust does appear, it wipes away easily, back down to the patina...