So, in the event of a real incident, your kids would not know the drill, how to respond, and could disrupt and endanger the whole effort
No. Historically many school shootings happen within a mile or so of an active drill, time after time after time. The drill is NEVER at the site of the shooting, but is close enough to give cover for a larger than usual LEO presence in the area, and ‘splain away a faster that usual (but often ineffectual) response.
Pay attention next time, (which I predict will be soon, I’ll go further out on a limb and guess Halloween) or you can dig out the historical data, unless google has Fahrenheit 404’d the articles.