I've seen a handful of news articles recently concerning law enforcement agencies branding photography as a terrorism related activity.
A new campaign by the Chicago Transit Authority suggests that civilians report photographers the same way they should report unattended packages and suspicious persons (coverage by NBC Chicago: Losing Focus: CTA Warns Against Excessive Photography).
There was also a recent article about photographers in the United Kingdom protesting the police's ability (under anti-terrorism laws) to stop and search anyone for any or no reason; which, apparently, has been used as the excuse to harass photographers (CNN is carrying this story: Photographers protest over UK terror law). Luckily for them the European Court of Human Rights ruled that this legal power is a violation human rights.
But, on to the main point (there are hundreds of similar articles about photographers being harassed under the guise of anti-terrorism). At first glance we would probably think that it likely for terrorists (or would-be terrorists) to take photographs of the locations they're planning to attack. It's what happens in all the movies, right? Well, it is, in fact, entirely wrong.
I'd highly recommend reading through Bruce Schneier's essay on the matter from June 2008: The War on Photography. He covers the topic far better than I could.
Go read the whole thing (it's only about a page), but here's the most relevant excerpts:
Clearly any terrorist is going to first photograph his target, so vigilance is required.
Except that it's nonsense. The 9/11 terrorists didn't photograph anything. Nor did the London transport bombers, the Madrid subway bombers, or the liquid bombers arrested in 2006. Timothy McVeigh didn't photograph the Oklahoma City Federal Building. The Unabomber didn't photograph anything; neither did shoe-bomber Richard Reid. Photographs aren't being found amongst the papers of Palestinian suicide bombers. The IRA wasn't known for its photography. Even those manufactured terrorist plots that the US government likes to talk about -- the Ft. Dix terrorists, the JFK airport bombers, the Miami 7, the Lackawanna 6 -- no photography.
So why the focus on photography?
Because it's a movie-plot threat.
A movie-plot threat is a specific threat, vivid in our minds like the plot of a movie. You remember them from the months after the 9/11 attacks: anthrax spread from crop dusters, a contaminated milk supply, terrorist scuba divers armed with almanacs. Our imaginations run wild with detailed and specific threats, from the news, and from actual movies and television shows. These movie plots resonate in our minds and in the minds of others we talk to. And many of us get scared.
Now go read the whole article to see why movie-plot threats are the stupidest thing to guard against.
And don't harass photographers for taking pictures.