It can twist in your pocket and when you are in a dangerous situation you have no time to check if it is twisted open or closed.

i heard there's also a spray that hard to wash away, so the area around your eyes will be colored in blue when you get some in your eyes

I am also thinking what weapon I will carry around with me in future.

 

I want to be able to outrange a knife, so maybe I will try to build a tazergun or maybe a foldable spear.

i remember carrying paper knife with me at school to scary the bullies, but eventually the teacher freaked out and asked me to give all my paper knives away (i use the paper knives to sharpen the pencils, since i don't really like pencil sharpeners), and we had a discussion about bullying later

How does it make anything better when you get beat up by a blue guy?

idk ask the inventor of this spray, this just what popped up in my head after reading the post