I always have at least one knife on me. Usually a Chris Reeves Small Sebenza (when in the office…on the dressier side of bsuiness casual). I also often carry a Spyderco Endura (hiking, weekends in shorts, or when I might lose it), or a William Henry carbon fiber and damascus (when I’m feeleing fancy).
I do not, though, use them along with KM, or any other martial art. My knives are tools, not weapons. I train so that I do not need to deploy edged weapons. If life becomes so dangerous that an edged weapon is required, I will carry (.45 ACP beats VG-10 or ZDP-189 any day!) I alo would carry a comtech stinger, kappo stick or other force multiplier before an edged tool for weapon use. I fully support others who choose to do otherwise, this just seems to work for me.