I just can't figure this one out yet, after three years, and in the same location in Kentucky near the Cincinnati border, I continue to find this situation in spite of the rules that are included in Article 525 - Carnivals, Circuses, Fairs and Similar Events.
Someone may have missed this, but in the real world it's a problem, and no matter how hard we try to enforce the rules, there will be someone who has some problem with enforcement. Sometimes politics are the reasons; other times low standards of behaviour are the norm.
See Section 525-13(f) Protection. Flexible cords or cables run on the ground, where accessible to the public, shall be covered with approved nonconductive mats. Cables and mats shall be arranged so as not to present a tripping hazard.