The expert commission appointed by Virginia Governor Tim Kane has concluded that one of the mistakes made by Virginia Tech officials during mass killer Seung Hui Cho's rampage last spring, was waiting two hours to alert students and employees that murders had taken place. (read a summary in the Washington Post). In this day of instant messaging and peanut allergy warnings on the glass case at Starbucks it may seem obvious in retrospect that University officials should have sent out notice. Indeed universities are required by federal law to make crime information widely available.
I wonder however about the value of making everyone aware that a homicide has just taken place, especially when, as here, the police are quite confident that they have a suspect. After all, it is the extremely rare murderer who is out to kill just anyone they can find (although for that reason they are especially terrifying and movies find them irresistible), most killers have very specific reasons for using violence against very specific people (specific, not good).
A campus like Virginia Tech (or Berkeley for that matter) is a small city of 30 to 50 thousand people. If you live in a city do you really want the police to alert you right away that a murder has taken place? The "costs" of such information include a level of fear and trauma that may not be trivial. Since follow up information on what happened is far less likely to succeed in the typical case of a single incident killing, the informed subject may never learn the ultimately "reassuring" (even if desperately sad) facts, e.g., that the victim and perpetrator had known each other and endured interpersonal violence for years.
Americans often act in their lives as if the chances were relatively good that sudden and relentless violence might descend on them. Events like 9/11 and Virginia Tech remind us that these fears are not totally baseless. But the precautions we take are not costless either. They have effects on our physical and mental health, as well as in the inefficiency of environments that have become heavily securitized (notice how often security delays are now part of your internet experience).
Sometimes what you don't know can kill you. Sometimes what you know can kill you too.