From what I've read in the past a lot of this is interpretation (just like open carrying in legal areas of a state and getting hassled, or worse) even if it looks ok under the law. I carry a 5" version of a yawara stick and may get hassled in Missouri. I'm also carrying a <4" Buck 110 and one to two firearms. It would seem a moot point to come under fire for the yawara stick. If I recall the big issue for interpretation in MO might be about a WEAPON capable of death or serious bodily injury so someone w/o a CCW license might have to deal with the more so than someone with the license. But my yawara stick is a self defense TOOL for reacting to attacks, not starting one.
However, I would never carry this thing in some states (IL). Heck, I can't even carry my Buck 110 boyscout style pocket knife in IA or NE.
I recommend you look at the justification for force, lethal force, CCW prohibitions, etc. when you do your research and remember the interpretation LEO by LEO can be the real crutch.