Today the Los Angeles Unified School District was closed due to what was called a credible threat. Allegedly someone called in a bomb threat and the entire district was shut down. Parents were robo alerted to pickup their kids and the entire country sat to watch.
Tonight it looks very much like it was a hoax. New York city schools got the same threat and stayed open. Apparently the vetting process that led to these decisions is very different. A source said earlier today that Los Angeles officials did not seek advice from the FBI before closing schools for the day.
There are obvious risks with such decisions. Potential enemies of various types could be testing reactions. Obviously people who just want to shut down school can keep sending threats.
Officials need to review their security. They should review the criteria that bring about responses and should certainly consult the FBI when there is a perceived threat. It is easy to say you always must err on the side of safety, but a mistaken reaction can turn people complacent. Complacency can be deadly.