A lockdown that locks them out

A school in Colorado got the idea of a lockdown right, although I'm not sure it wasn't more by accident than anything else. They had a lockdown at 6.am., and kept students away from the school until they determined it was safe.

I'm not sure the whole thing wasn't pointless, but at least it was aimed in the right direction, towards actually protecting students rather than just creating an appearance of doing something.