I brought up this issue a couple years ago with the bonneville county sherrif. They mentioned that a double edged boot knife was alright if open carried, but required a permit if concealed. The big issued seemed to be intent too. Although, its hard to prove a double edged knife as a tool and not an assault weapon. I'd talk to the local county sherriff. If you have a concealed firearm permit, you probably have less worry, although I do not believe it covers knifes. Be mindful that this is only within cities. The public seems to get hairy about open or concealed carry anything anymore, as you have probably encountered.