On another thread we had a discussion on when to let an Leo if you are carrying knife. People have their own perceptions on what they consider dangerous and what is not. Some of the most useful tools I gained from my martial arts training was the ability to safely deal with an attacker with a knife. Mainly what students had to do is take away the wooden knife from various attacks. It becomes vary apparent what works and what doesn't. What stuck me as odd is the size of the knife we started out with. It was big and it was a stilleto. Then as we got proficient with that the knife grew smaller. I asked my instructor about this she said the smaller the knife the more dangerous it is and here is the reason: A big knife you can see, is harder to hide and in general moves slower so it is easier for us to take it away. You can keep track of it easier, you always know where it is and which hand it in. A smaller knife is easier to hide and a lot harder to keep track of and generally you can't tell when they are going to strike with it because its harder do judge the correct distance. Plus a smaller knife has less places you can get a hold on to when you try to remove it from their hands. The most dangerous knife in our art is an exacto. It slips into the hand and you can barely see the blade so if someone were to hit you with it, by the time you realize there is a little piece of metal in their hand it's too late. Also from her experience my teacher said a favorite trick of girl gang members was to hide a razor blade between the fingers when they got into a fight they would slap someone and slash their faces. Think about it you see an open hand coming at you, no real danger there so you might just wanna take it and you wind up with you face permanently scarred after stitches. The whole purpose I'm giving you this bedtime story kids? don't let anyone confrontational into your personal space. "What's your personal space?" You might ask. Well stand up and get in front of a mirror. Stick your arm straight out with your fingers fully extended and touch the mirror. That is your personal space in order for an attacker without any weapon to get they would have to take a step and your mind has time enough to tell your body to react to defend yourself. If they have a knife or bat the extension of your arm to the end of the weapon is your personal space. Don't let them sneak into that space. The other thing I want to tell you? If it's got an edge to it it is dangerous, sharp pointy things are dangerous. That's why banning pocket knives and box knives on a plane is ludicrous, because anything can become sharp and kill you.