I carry a leatherman on my tool belt, use it almost once every show, and I have a Swiss Army knife in my bag - it's wine country, you don't go anywhere without a corkscrew, really - and both have blades that are ok for cutting cheese, apples or opening letters, but they are not real knifes when you need to do some serious cutting, and in the case of the Swiss, it does not have a true locking blade, which again, when you're really cutting you don't want the thing folding back on you.
And what I have against carrying weapons, is not that I don't like them, I'm a country girl in a lot of way, and I dig guns, and I'm pretty good with them, but its the way they change the way people think.
It's simple to me.
If you wouldn't walk down that street, or alley, or go to that place without a gun, you most likely ought to stay the hell out of there even if you have one.
If carrying a weapon changes that basic reality in your head, then you have put yourself in greater danger and are a threat to your self.