In my knife carrying days, I find that the shit Mouse said proves to be pretty true with cops.
The shitty thing is....Wish cops they give you less shit if your knife is NOT concealed....however you have more of an advantage on your attacker if it is.
When cops gimmie shit about my knife, i just explain that is for my food, act real calm like it aint no deal, and they lay off.
Sometimes, I carry a big rock on me, just to keep in my hand inside my hoodie pocket if shit gets real sketchy...
For free and legal mase....I heard ground up chilly peppers in water is good? Although, ive never tried it.
I like the idea about the wasp spray....