Women in Orange - how an outfit can get you arrested

I just came across something rather interesting, something I’ve never actually heard about before, but I assume it was only because of my ignorance - illegal advertising at sport events (or maybe any sort of events).

Dutch women dressed in orange outfits who appeared at Wold Cup game Holland vs. Denmark were arrested on the grounds of so called ‘ambush marketing’. When I heard about this my first impression was: well, they didn’t do anything wrong. They just wore colours of the team they supported.