Besides the caveat given by ChaseReynolds above, I feel that as long as the school has actually trained its faculty on how to react if there is an active shooter, the drill would be beneficial. If no one's ever specified what to do for a fire drill, having a fake fire drill would be equally useless.
The quote below makes me believe that no one has actually thought up a site-specific action plan in case of an AS scenario.
School staff had received training from the Union County Sheriff's Office on active shooting scenarios, but many educators were caught by surprise and unprepared to handle the situation, according to The Oregonian.
Read more: http://www.foxnews.com/us/2013/05/02...#ixzz2S96qATvU