For one thing, they happen to be illegal in North Carolina.
You can be arrested for carrying any assisted-opening knife.
A switch blade will get you jail time.
An out-the -front type knife will get you prison time for carrying a weapon of mass destruction.
But, any "typical pocket knife", whatever the Hell that is, can be confiscated using "officer's discretion", without being arrested.
That last one means that if the officer takes a liking to your custom built, perfectly legal pocket knife, he may take it home with him and dare you to say a single word about it.
Been there, had that done to me.
You may also be confiscated "at the officer's discretion", jailed with no charges for 72 hours, released and then immediately picked right back up for another 72 hours, and on and on.
Get the picture? North Carolina is now a de facto police state where all judges automatically take the side of the police. Unless you happen to be a rich Republican, of course.
A "wink, wink, nudge, nudge, pass the campaign contribution" will make you pure as the driven snow. If you're the same color as the driven snow, that is.
Otherwise, that's bribery and you just became an example.
I used to love my home state. Now, I don't feel safe going to the grocery store while carrying any kind of protection at all.
No doubt this post will disappear ASAP. Those who do get to read it, remember it. And learn your own state's knife laws and how they may be interpreted.