If it looks like you might have a weapon, you can get arrested and/or shot.
Empty holsters/sheaths may be okay, but it may cause people and cops to ask, "Where are the weapons?" Cops can possibly suspect you of carrying a concealed weapon. If you don't have a weapon on you, it'll be an unfounded accusation. But they may have to stop, detain, and search you to confirm that first (actually experienced that first hand).
Eh, you wanna carry anything resembling a weapon or anything carrying a weapon, go ahead but acknowledge the risk.