I used to carry a knife, but realized that all it tends to do is escalate... if you let them see it.
I recall learning a long time ago that 'shaolin monks' learned to have a mindset that anything that came to their hand, would be a weapon. I try to follow the same, to the point of having led practices where we'll roll up magazines to use as batons, where we've taken pennies and learned how to apply them to pressure points.
I occasionally fly, and use the metro system, as most people do. And when I do, while I don't carry a knife, I will not get on a plane without a sharpened pencil, and a pen.
The nice thing about them is they dont have to be lethal, they work just as well as any koga baton if you reverse the point it effectively becomes the pommel of a knife, which is a much less... lethal approach to dealing with uppity folks.
I've found that ball point pens are the most durable. I think it has to do with how they are mold in the factory, and instead of it being of the plastic being formed in a horizontal way, it's vertical, so the stresses are easier dispersed in the weapon. Lord knows if you use a multi jointed pen (or multipart) you hit something with it enough, the whole thing will just disintigrate in one's hands.
I stick with ball point- they're sharper, and more useful for a tearing cut, which with a pen is a lot less... ah, lethal again. I prefer to maim, or mark, before taking, if you know what I mean.
It's just, ever since 911, even if I was in the 6th grade then, I've had the mentality that if I'm on a plane and that goes down, at least someone there has something to stick into those assailants, and the willingness, and knowledge of how to.
Remember, they are more like the pick of a sai than anything else. Just a lot sharper.
If I weren't going for light cuts, I'd be going for gouges at the tender vitals; inner clavicle, under-jaw, temple, etc. Pen's require precision, which is a bit different than I think knives allow, which can be to go willy-nilly.
The teacher who taught me how to really use a knife always cautioned it was the most dangerous weapon; anyone can pick it up, and you don't even have to aim it to do real damage either. We treat knives with even more severity than guns- they are vastly more applicable, utilizable, and easy to fashion and come across.
I'd actually say if it came down to someone pulling a knife on you, and you've got the choice between your pen, or car keys, I'd go for the latter.
I've modded my keys so that they're maximized as weapons; can be used in the same manner as a nunchuk- the steel zip-line can punch holes in cardboard and a wooden fence, and it can be easily weilded as a knife, or set of steel knuckles.
Keys are much more versatile, especially when sharpened. I'm happy to post a video- I'm actually trying to get more people to weaponize their keys in the sake of self-defense, tho my apologies if I've gone off a tangent.
