There are some valid points posted above. Your boss can dictate what you can and can't do while on the job to maintain your job; that's why you're being paid.
It is true that "waving it around" is careless and would cause concern. It should.
However, giving in to sheep is never acceptable. If you're going about your business and not an obvious threat and not causing harm, not being paid to do something else, it is none of anyone's business what you are doing. If someone decides that they don't like me wearing a yellow shirt because they find it offensive, too bad. Some people may not like my accent, me being from the South, that's their problem.
"Giving in" is exactly what the sheep want you to do. "Conform! Conform!" is their clarion call. Worrying about legislation because you are lawfully carrying and using an edged tool is ludicrous. That's already sheep thought.
You can help create acceptable social behaviors by showing what you do is peaceable and helpful, or you can give in muttering, "You're right, I don't know what I was thinking." And have to change your actions because of someone else's phobias for the rest of your life.