by Parataxis
See, my initial thought was that 'any sticker' would prevail, and that the 'scars or cities' was just to provide examples. (Since there's no 'only' in the rule.)That said, my board is still unplayed, so I've no idea how either way would affect playability. It's all theoretical to me at this point.
I'm actually a bit surprised that this hasn't been clarified before. *shrug*