Many people have noticed that officials have held a drill on the day of these so-called terror attacks in (from what I’ve seen) every case.
This video covers the specifics of the recent Paris attacks, including catching a French official flat footed, and discusses several of the other cases. The video doesn’t include Sandy Hook, amongst others, but it was true at Sandy Hook, also.
Worth a few minutes to watch.
And whilst I’m on Paris, I love this alternative approach to demonstrating in the wake of the COP-21 protest bans.