There are public spaces, and then there are private spaces open to the public. I fight this one all the time with a local park. It is a park that is not city owned public, but privately operated and open to the public. They have a very strict photography policy, and their "employees" will interfere with you if you do not have "permission".

I believe shopping malls are private spaces open to the public. The point is that I would not be shocked to see that there are different rules regarding public spaces vs private spaces open to the public.