Yeh, it's just compare between padlock and keys.
I edited my post #23 on cane after you responded. Did you see the part I practice hitting the knee on my first strike instead of the head and the upper body? What do you think the way to avoid people grabbing the cane.
My thoughts on the cane would be, if you're carrying a cane for legitimate health reasons, by all means learn how to use it as a defensive weapon as best as possible. I think that's just smart.
Regarding carrying it when you don't need it, I think it's important not to overestimate the utility, and superiority that the cane might hypothetically give you. Again I think it has serious limitations. One limitation being how much room you need to swing that thing, and how you typically have very little room when fighting in hallways, living rooms, airplanes, wherever you're in a real self-defense situation.
Understand that you are now employing a lethal force weapon, that changes the dynamic of when the cane can be used, and when it can't be used. But now you have it so it's a factor in almost any engagement you get into. In some ways turning every confrontation into a situation where it's potentially lethal. Or at least it may legitimately be viewed that way by law enforcement.
If you're going to use it I would make a serious study of kendo or kenjutsu. I think that would be the best way to employ the cane myself. As far as hitting the knee, this could certainly be done precisely, using blade deception found in kendo training. Of course this requires a lot of room to swing a weapon like that, you're just as likely to hit an innocent person nearby trying to employ these techniques on an airplane or any type of space in a real environment. What happens after you hit somebody in the knee, depends on multiple factors.
You might cripple them, or you might be off by an inch, but still cause enough pain to get them to back away. Of course that pain could also motivate them to move forward and grab a hold of the cane before you have a chance to retract it for a second strike.
So many factors here, but I think the main thing would be if I personally was going to carry a cane, I would seriously study how to use it, avoiding almost all of the fancy grappling techniques, although I'm sure some of them could work. And I would rely on my grappling skills to retain the cane, and or get it back if someone took it from me.
I think someone holding a cane could be a legitimate deterrence, and cause someone not to attack in the first place. This I believe.