It will still be easier to pull the fire alarm, and yet, that doesn't even happen terribly often. Every year some kids here and there get the bright idea... but seldom has it been a real issue, and dealing with it is hardly going to take anything new.
A kid could do the same thing right now with some fireworks and some creativity. Explosions or gunshots will be reported to the police as is, they will cause panic as is..... this system really does nothing new except reduce the time to report to the police.
So really, in terms of what mischief kids can cause, its nothing new.
Now, if this system calms people down about the risk then maybe it even makes sense. At least, maybe it does in contrast to most of the other short term proposals. Certainly more sense than posting armed gaurds, training teachers, or disarming society.
It certainly isn't a real solution to anything. However, I doubt there are any real short term ones when the real need is the revamping of mental health services that is unlikely to happen and have their desired impact in the time frames where people demand to see "something" be done.
Course, that assumes the whole system isn't just a money hole being used to milk the system....which....is a big assumption when it comes to the government and its contractors.