Ever since I got smacked at the Port of Tampa for taking pictures, I've been thinking about what the real reasons are for preventing people from photographing sites because this would do
nothing to prevent terrorism. Public transportation, trains, and industrial plants are all high on the list. I was quickly reminded that photographers often bring to light a lot issues with these things: photographing industrial pollution and waste mismangement, transportation safety issues, etc. A lot of people are also indicating that it is being done because no revenue is gained from people taking photographs and to gain permission now costs money. Many state parks now
charge huge fees (scroll down to "Photography Fees") and will stop you even if you have a professional-looking camera (any SLR, anything with a long lens, anything that is not a dispo, etc). There is a lot of money to be made and even more illegal/hazardous activity to cover up by prohibiting photography.
It is extremely important that these rights remain. And, to anyone else out there who loves to carry a camera around town, I highly suggest you print out and carry with you
The Photographer's Right Booklet.
Forgotten New York
has a photographic and written account of the protest.