Here's a case where a Marine was carrying a knife and used it in self-defense while in Waikiki.
http://www.staradvertiser.com/news/breaking/Police_investigate_Waikiki_stabbing_make_arrest.html
I can't help but think that that's bullshit. Not the results, I'm glad he was not charged with anything - as it should be. The lack of any clear laws on self-defense - or the carrying of tools for the purpose of self-defense - places Justice on the whim of a few people, based on who-knows-what since it's not printed anywhere. If it is, then I stand corrected. Otherwise, this is bureaucrtic bullshit. Kind of like our firearm laws. On one hand, I'm ecstatic that a law wasn't needed to exercise common sense and letting the ambushed victim(s) go. On the other hand, I'm afraid in the political climate Hawaii is in, common sense is not all that common.
What kind of knife was used? I'm guessing information like that is ommitted so it doesn't give the public ideas of what they could carry for self-defense. If they prosecuted him, it would have kicked up a shit-storm, have snapped a percentage of people out of droning and being told what to do, and encouraged a reform that would have garnered the support of the military and mainland visitors abroad. If we knew what kind of knife he had, and he was illegally carrying an illegal knife on him, then they should've prosecuted him for it. I sure as hell hope that he was carrying something other than a dagger or dirk or butterfly knife, which are indicated as illegal. If he was indeed carrying one of those three types of knives, but let him go to avoid a political clusterf**k, then I ask: What the f**k ever happened to Justice and obeying laws, instead of doing what best works for you and your own agenda? Where's the integrity? Call me naive, but this is all bullshit.
Even if it were a pocket knife and completely within what may be "legal" means of carrying, there is no clear definition of legal carrying of tools for self-defense, and therefore retains it's status of bullshitmanship.