I believe most, if not all, states do not “allow” concealing a sword in public. In Virginia it is illegal to CC, but it is legal to OC a sword.
I think that’s true in my state. Kind of ironic, isn’t it? I can conceal carry a firearm, but not a pointy stick.
I’m 71 and currently use a cane and walking stick. I have a 1st degree black belt in Okinawa Shorin-Rhu karate. My bow staff weapon training is appropriate for cane use or walking stick. A walking stick would be preferred as it’s longer and closer to my bow staff length.
Basically you want to strike certain vulnerable places. The side of the knee strike can take someone down. A strike to the temple region of the head can knock someone out. Of course, a groin shot, which may be difficult to do , can take someone down. For the longer stick weapon, a well aimed eye poke , while more difficult to do, can certainly stop someone.
My preference would be to vocalize to the person approaching to stop. Be sure to have your cane in your strong side first. A fast strike to the knee would be my preference, but if you do it needs to be very hard and quick.
Escrima is a good martial art to study if you want to “up” your cane game.
A word of caution—don’t try sparring if you wear bi-focals, and don’t ask how I know this!
There are also canes with a concealed flask inside. 
I am just now reached the point where I need to incorporate a cane in my EDC. I chose the following cane for several reasons. 1 in round Heartwood hickory, was able to customize to my height I like the looks of it. TSA approved so I can carry it anywhere. I just placed the order a few days ago but it’s very similar to the one below except there is no grip pattern at the bottom of the cane only the middle and the top. I am left-handed. I need to utilize the cane on my right side. That was just luck since it won’t interfere much with my drawstroke from behind the left hip. I suppose I’ll just need to drop it if I ever had to access my firearm. Also I need to look into using in a close quarter self-defense situation. I’m sure some training would be advisable.
Great for trips to the post office and other prohibited places and so-called gun free zones.
Saw a docu recently of Bruce Lee mentioning he learned some form of escrima or arnis from Dan Inosanto.

