really?
curious to where this may be in the US.
Double edged knives (daggers) are most generally unacceptable.
Where?
Texas until recently, for one.
Michigan, New Mexico, and Colorado still won't let you carry double-edged "concealed". Felony crime in Michigan, if the charge sticks.
Denver has some goofy measuring standard for double-edged knives, making them effectively illegal. Colorado passed some recent laws, unsure if they included a preemption clause to shut down silly city laws.