Turning Cell Phones off in Tunnels
In response to the London bombings, officials turned off cell phones in tunnels around New York City, in an attempt to thwart bombers who might use cell phones as remote triggering devices. (Phone service has been restored in two of the four tunnels. As far as I know, it is still not available in th other two.)
This is as idiotic as it gets. It’s a perfect example of what I call “movie plot security”: imagining a particular scenario rather than focusing on the broad threats. It’s completely useless if a terrorist uses something other than a cell phone: a kitchen timer, for example. Even worse, it harms security in the general case. Have people forgotten how cell phones saved lives on 9/11? Communications benefits the defenders far more than it benefits the attackers.