I just had this conversation with some people at work. A guy from another department came to my area (IT) to discuss a project and saw me cutting open a box with whatever I was EDCing that day. He commented that he thought our company banned knives. Of course, at that point, four or five other guys in my department all flipped open their various folders. Our "guest" assured us that our employee handbook stated that knives were banned, but I checked and found that not to be the case. Guns, yes, but knives, no.
Of course, every now and then, someone will ask why so-and-so is bringing a weapon to work, and one of us always feels compelled to state that a knife is a tool.