Knife laws in the US (and elsewhere) are complete bullshit.

For example, in Texas you can't carry a switchblade or balisong (butterfly knife) of any length. What's wrong with that, you ask?

1. In Texas you can carry a fixed blade up to 5 and 1/2 inches in length, so long as it's not double edged. This includes knives with upper and lower guards. A fixed blade "opens" faster than any automatic knife and if well made is also stronger than any folder. So why in the world are they legal when other knives are banned?

Even if you don't know a whole lot about knives, which looks more like a purpose-made weapon: this or this?

2. Contrary to popular belief, butterfly knives are not "just for show" or necessarily designed for combat. They have numerous advantages over other folding knives. The safety advantage of a balisong is that when it's open, the handles lock the tang in place making it almost as strong as a fixed blade. The only way for the "lock" to fail is for one of the components to break completely, which won't happen so long as the knife is of good quality and isn't abused. Unlike other folding knives, if one does fail then it won't close onto your hand. They're also good for situations in which you don't have two hands to open a knife. Again, a fixed blade can be deployed faster than any butterfly knife and they're completely legal.

TL:DR butterfly knives aren't any more dangerous than any other folding knife and are only banned because they look scary.

Another annoyance is that it's illegal to import butterfly knives into the US. The problem with that is that cheap balisong from countries like China still make it in. Why? Customs doesn't catch most of the knives and they're so cheaply manufactured that it doesn't matter if a few are seized; the company can still make a profit. With a nice knife that sells for $200 or more this obviously isn't the case. So essentially, the only thing the ban does is keep high-quality foreign knives out of the US and the cheap crap in.

3. Thumb stud knives are legal to own in Texas and you can pick up a shitty one at the mall or any corner store for $5 to $20. These are exactly the kind of weapons that criminals would actually use: cheap and concealable. I made the mistake of purchasing one of these, before I did any research about knives. It's very cheaply made but it opens fast enough to beat a switchblade and would be more than sufficient if I wanted to shank someone. Again, these are legal but a balisong isn't.

So why don't we just impose legal standards on the quality of pocket knives so that the cheap shit disappears, instead of arbitrarily banning certain types of knives? Cheap shit is what's used in crime and the extant laws aren't affecting anyone except for collectors. If butterfly knives were legal, but there were standards on their manufacture then they'd all cost at least $80 (entry level for a good balisong). No thug is going to pay $80 to stab someone. Of course, there will still be knife violence. That can never be eliminated completely. But at least then the law would allow freedom for collectors, and there certainly wouldn't be any more violence as a result.

I know that will never happen though. There's not any powerful groups that are pushing to change knife laws and knives have a bad public perception that isn't going to change anytime soon. I'll bet that in a few decades we'll have to use plastic knives in our own kitchens. Ah well.