Check out this article from the Washington Times. Seems as though Canadians, most of whom when visiting Europe wear a Canadian flag baseball cap, a Canadian flag T-shirt, and have sewn a Canadian flag patch on their backpacks just so no one will think they're Americans, have been warned that they'd better not because Canadians may be targets for Islamic terrorists. I'm splitting my sides laughing at the irony. The Wash Times article mentions that some chickenshit Americans try to pass themselves off as Canadians while overseas, which I have run across and find repulsive.
I remember that back around Gulf War I, the State Department sent out guidelines for Americans to follow while in Europe. We were supposed to avoid wearing baseball caps, avoid chewing gum, avoid wearing American sports-team or university clothes, avoid wearing jeans and sneakers, avoid listening to Walkmans, avoid going to American chain restaurants, avoid being seen with American newspapers, and avoid talking loudly in English in order to disguise our Americanness. Someone commented to me at the time that except for the last two, the list of Amerikanisch things to avoid could perfectly well have described any Spanish college kid.
By the way, the once-ubiquitous Walkman, which everyone in Spain used to carry around and listen to while on public transport, has been completely replaced by the mobile phone, which everyone in Spain now carries around and fools with on public transport.