I wonder how long that has been in effect. Growing up and later working in Superior, I noticed that people commonly took weapons into bars and restaurants to show them off to friends and, occasionally, to eliminate rivals for lady's affections. Myself, I most recall sitting in the Triple X bar when an Apache lady who had been arguing with her husband left the bar and returned with an axe. She took a couple of good licks at him (missing) and chased her hubby out the side door. He was apparently able to hide as I saw him at work the next swing shift.
Ever since that day, I have strongly supported the banning of assult axes.