Recently, in a Highrise Construction thread, an individual wrote of his experience in Chicago while photographing a structure. This individual was approached by a security guard from one of the most prominent structures in Chicago, the Aon Building. The security guard informed him that taking pictures of the Aon Building was prohibited due to "Homeland Security Concerns". I have heard of many others with similar stories. I experienced a similar confrontation a couple years ago, being told that I could not photograph a certain structure.
When I was approached, it would have been great to have a response for this security guard, letting him know that I am aware of my rights as a citizen. I have done some searching around and found a couple sources. Probably the best source I have found so far is from an Attourney named Bert P. Krages II. Perhaps the laws have changed since, but here is his publications:
If anybody has anything to add, please do.