Probably any public gathering place, like parks and plazas, and major landmarks and buildings, would be fair game for photography restrictions, although it would be hard to enforce. Last year in Denver, during the conference, I found an old building with some amazing WPA-era murals just inside the entry. I took photos of all of them, and as I was focusing for the last one, the security guard came out and yelled at me, told me photos of the building were forbidden. I'm not sure what kind of offices were in there, but I'm pretty sure it was a private office, and the photo ban may have been to protect the murals from flash exposure. They were encased in acrylic, and getting them w/out the flash was hard.
They've just announced this morning that more attacks of some kind are anticipated this summer, which will make photography even more difficult, more than likely. Wonder if they'll ban cameras at sporting events?
