Why can't you take pictures in a store?

Answer 1

These are store policies. Basically, a store would be just like if you went to a stranger's home and wanted to take pictures inside it. A store is owned; therefore, it is private property---not public property. Now, you could take a picture of the store's sign outside, because being outside, it is a public area. BUT if the store (or mall) owns the sidewalk or parking lot on which you stand to take the picture, they can demand you leave if they don't want photographs taken. It is primarily the public versus private concept of personal and social boundaries-- if you want to take pictures, go to your own property or public property.

Stores may have other concerns about inside Photography, too. But it's mostly because it is their land / building and so, their right to say what you can and cannot do there.