Additionally (I thought about it a bit more), this is not my preferred weapon, nor am I saying you shouldn't be open to other options. Just as many of us carry matches, and a lighter, a magnesium block, and a Sparklite, you should prepare yourself with a similar array of self defense options - not rely solely on one that, while effective, may not be available to you at all times. If the opportunity to talk my way out presents itself, or I can avoid the situation altogether, that will be the ideal course of action. If I can legally pack something more effective (my EDC handgun or an ASP, for example) I will do so, and that will be the "go-to" weapon. If I can quickly and safely pick up a better improvised weapon, I will do so.

But if faced with the option of throwing my book/Nalgene/carry-on bag and hoping to hit something soft, or standing and fighting with something I'm familiar and confident with, even if it is not the 'best' tool, the choice is obvious. This is just one more option available to me. With life and limb on the line, losing my keys would be of little concern to me - I can get new ones.

I'm certainly open to suggestion. If there is something else available that I already carry everyday and is legal and low-vis just about everywhere, by all means, educate me (I'm not being smart-alecky here - if you know of something better, I'd like to know it, too).

A quick note on knife fighting: I've undergone some "knife-fighting" training. There is no such thing as a one-on-one knife fight. Sure there is the old maxim "if you are in a knife fight, you will get cut", but I've seen the effects of a small knife on flesh, and I'd have to be absolutely desperate to stay in a fight should a knife present itself against me. It doesn't take much at all to cripple someone with a knife, and I'm not willing to "take that cut". If I had a weapon that extended my range, then it might be a different story. The knife fighting community refers to the "Mexican sacrificial limb" - so named for the country of its origin. The foward hand is presented as a target, to draw your opponent in. Many arms have been rendered useless for life using this technique, often from a single strike. Knives are extremely nasty weapons, and I would gladly turn tail and run from an assailant with a knife if the only option was going mano y mano.