In Canada, buildings can only be copyrighted for the purposes of reproduction - thus, I can take a picture of your building (and reprint it in books/online/magazines/etc.) but what I can't do is use the pictures to erect a duplicate of the building across the street. Buildings have no expectation of privacy and thus can be photographed as much as you want. As long as I am not trespassing, I can all of the pictures I want of any structure and if caught trespassing, it is the trespassing that is the issue, not the taking of the photos.
However, as it is a mall in Canada, they can refuse to permit photos but they have to clearly identify this when one enters the mall and they never have permission to make you delete/destroy them without a judge's order. Because - if it is illegal to take pictures, you are destroying evidence of a crime; if it is not illegal, they can't force you to comply just because they want to.