A school in Pennsylvania went into full-on lockdown when some children who were making a video about the immune system, which involved some sort of play-fighting with an umbrella, were mistaken for gun-toting lunatics. There is a balance between disaster preparedness and "when in trouble, or in doubt, run in circles, scream and shout," and this isn't it. A deputy chief in the video excuses the exercise because the kids were doing something "suspicious," but of course, there's a difference between being secure and being terrified of anything out-of-the-ordinary. Alerting parents and locking down kids when nothing bad is happening isn't making us more secure, it's making us more scared.
School Goes Into Lockdown — Complete with Kids Crying in Closet — Over Umbrella