One can easily be snuffed with a blade much shorter than this...
I think that anyone that wishes to carry a weapon of any sort, should first have to undergo victim affinity training. Ergo, a potential gun owner would, before being considered for ownership of a licensed firearm, be shot in a non-vital organ, in a controlled environment, by a weapons control commissioner. Likewise, a person wishing to carry a knife on his/her person, should first be subject to state sanctioned stabbing...
Those carrying weapons without proper victim affinity training (and the scars to prove it) should have this training imposed summarily by the arresting officers...