Someone told me about this sign, seen in the window of a Family Dollar store in Minnesota.
The person that told me about this sign said she'd spoken to an employee of the store, who just said, "We were told to put the sign up." I don't know who told them to put it up.
I emailed the corporate office, explaining the problem with the sign. I received a response in less than one hour, assuring me the sign would be removed and that employees would be informed of the law. And the sign was indeed removed, less than one week later.
They got it right.