Just the opposite is true. Secondary weapons should be carried and deployed for the purpose of defeating and protecting oneself from an assault that does not clearly justify the use of deadly force. CN is alphachloroacetophenone or Tear Gas as many would call it. It's used in California a lot but many police departments don't use it anymore for a variety of reasons. It is fairly effective if sprayed in a normal person's throat, ear or directly in eyes.
Toxicity can be a problem.
One star rating. It is called CS after the names of the two British chemists who invented it in the late 1920's. Two star rating. OC is oleoresin capsicum or resin of red pepper. It is measured by percentage but that means nothing in and of itself.