A mall is a rather tricky thing. Even though it is private property, individuals have no reasonable exception of privacy that is why the owners restrict it. They also can cite copyright of architecture as they did with me once. I was taking pictures of christmas lights at an outdoor mall. However, I was only told that I had to leave. Copyright of the buildings and logos of the stores is something that I am not sure of either. I think I will ask my former media law professor about this. Of course the law is probably different in Canada.