Apparently, memories of disaster drills--now expanded to encompass man-made catastrophes, as well as natural ones--will have a decidedly different flavor for many present-day kids. Check this out from CNN.com; the video is interesting, too (thanks, BoingBoing). Maybe, rehearsals are now terrifying because the real thing isn't so abstract or impossible anymore.
Despite the themes' relative popularity in adult fiction, YA fiction that deals directly with terror and our current state of perpetual emergency (what color are we today?) has not yet been commercially successful, and I haven't noticed that anyone is acquiring it aggressively. Ultimately, it's not for me to say whether the marketplace of YA readers wants a YA take on the material that has occupied the likes of adult-fiction luminaries like Jonathan Safron Foer, John Updike, and Don DeLillo (with not inconsiderable commercial success, I might add). But what I can say is that terrorism and fear and our national obsession with preparedness must, I'm sure, be apparent in some form in day-to-day teenage experience--and anything that's there in real teenage experience is fair game for the fictional versions. In other words, even if you're not writing about terrorism, fear, paranoia, etc., how can they not affect the worlds of your books?