Whilst the closing of Andrews Air Force Base can be seen as waste of money and resources, it has been done for our safety. Terrorist attacks, which damage national security, have happened, and are happening, both at home and internationally. The decision, whilst costly, was done for the safety of the general public.
Yes, Andrews Air Force Base should have been locked down if there was a safety concern. It's always better to be safe than sorry. Also, at an Air Force Base, there is a concern about security breaches. It seem the lock down was absolutely right, regardless of the media's rush to report.
The consequences of not locking down the base had it been an actual active shooter would have been much worse, and the blame for allowing people to die or be shot would be fodder for more endless congressional investigations. Thank goodness they just locked the thing down and helped avoid another CSPAN Republican pulpit.
The lockdown inconvienced many people and caused unnessary delays. Personel should have been aware that the drill was going on and should not have overreacted because of a tweet that was sent out. Caution is helpful in some situations, but overreactions are a great way to cost people time and money.