The NYC subway system is thinking of banning photos on the platforms and trains. The argument is that somehow, photos of trains and platforms (not switching stations, conductor compartments, or control centres) will aid terrorists, and therefore that banning photos will make New Yorkers feel safer. So, basically, this is a stupid idea with an even stupider justification.
The Village Voice is holding a Forbidden Photos contest to shoot cool, arty pix of the NYC subway, and to kick it off, they've interviewed a bunch of photogs who shoot underground all the time about why they work on the subway:
More on this at Village Voice (cited from BoingBoing)