I'm pleased to report that the city of Pipestone, Minnesota (pop. 4000) has amended City Code ch. 10 § 10.01, subd. 1E to read

It is unlawful for any person to: ...

E. Possess any other dangerous article or substance for the purpose of being used unlawfully as a weapon against another; ...

It had earlier read,

It is unlawful for any person to: ...

E. Possess any other dangerous article or substance for the purpose of being used lawfully as a weapon against another; ...

I ran across this in doing research for my article on nonlethal weapons, and e-mailed the city attorney's office to ask whether this was a typo; I was told that it was, and then to my surprise was told that -- now that they knew about it -- the city would change it. Woohoo! Now that's high impact law reform work for you. I hope my dean gives me suitable credit.

(Note that the change happened a few months ago, but I only now remembered to check on whether it had indeed happened.)