Found a link on Flickr to a very interesting article today by "security guru" Bruce Schneier called "The War on Photography". In it Schneier talks about how terrorists from Timothy McVeigh to the IRA to the 9/11 hijackers weren't known to photograph their targets yet there is now a culture where photographers are seen as a threat to world security. Schneier's conclusion is that the reason for this is "Because it's a movie-plot threat" that can be "vivid in our minds".
Read the article at http://www.schneier.com/blog/archives/2008/06/the_war_on_phot.html. The comments after the article are also worth checking out.