Bet the FBI loves those!:-)
This area has gotten complicated in the last decade. At one time it was clear you could take pictures of people in public places, as long as you were not putting them in a false light - a picture of guy just going to work who was portrayed as a protestor might be an issue. Some states have passed privacy laws that limit the use of photos taken in public places and use for things other than news. While the target is advertising, fine art is in limbo because the courts have not clearly said that fine art photography is a first amendment activity. At some point one of these state laws will make it to the Supreme Court and we will get some guidance.