Looking at the Private Citizen Equipment Poll I was really surprised to see how few of the respondents carry pepper spray. I am guessing that people don’t really understand what a valuable defensive tool it can be.
Low level of force. The real value of pepper spray is that you can apply it very early in a potentially dangerous situation. Because it is such a low level of force it can be used much sooner and with less discrimination than higher levels of force. If somebody was closing the distance with you in a dark parking lot as soon as you command them to stop and they don’t you can spray them. You would have a hard time justifying the use of your firearm, but spraying them would be entirely reasonable.
Stand-off capability. Even with good unarmed combative/martial arts skills you will still need to be fighting at contact distance. Pepper spray could stop the fight before anyone is grabbing or striking you.
Deterrent value. Pepper spray separates the casually interested assailants from the truly motivated ones. Many of those who would be willing to fist fight (and escalate from there) will quit when they get sprayed, as soon as they get sprayed. Those that want to continue after an application are at least continuing the fight with a handicap.
Effectiveness. A common complaint is that doesn’t work all the time, but in fact shooting people doesn’t work all the time either. Just as with firearms, pepper spray is more effective with good training and tactics. Most people make the mistake of threatening to use it, rather than simply spraying and using the element of surprise. Giving the assailant the opportunity to mentally prepare for getting sprayed reduces its effectiveness.
A backstop for other levels of force. Even if pepper spray didn’t produce a “one shot stop”, using it before applying a higher level of force (such as striking) will provide some legal protection. This is the same process that law enforcement uses (situation permitting), to try and gain compliance with the least amount of harm. If doesn’t provide the desired result you haven’t lost anything.
Broadly legal. In most places pepper spray doesn’t have anything like the number of restrictions that other weapons do. Where I live the only place I can’t carry pepper spray is a courthouse or similar ’secured’ area. According to state law here, a 14 year old can carry pepper spray with their parents permission.
Why not? I really can’t think of a reason not to carry pepper spray. From the poll results I see that some people are carrying multiple handguns, but no less lethal tools? You have a far greater chance of needing a low level force option than you do of needing a primary handgun, let alone a secondary. Pepper spray isn’t the tool for a deadly force confrontation, but a handgun isn’t any help until the situation reaches that point.
