I'm gonna go out on a limb and say any time someone calls the cops to warn them, it's almost without exception NOT a real threat and instead just wanting to get a rise out of people.
Still, I definitely understand covering your bases and reacting as tho the threat is real. (It's better to be trolled 100 times than not act on a real thing once.)
It seems like a kind of "impossible situation" that just shouldn't be a thing, that the trolls would have this kind of leverage on law enforcement. It indicates that there's probably some underlying imbalance that's making the incentives like this.
Radical idea: Stop pretending that forcing people at schools to be unarmed is a good move.
It shouldn't even be complicated or controversial, except I guess there are people out there who don't want to give up on banning guns in general. So they don't want give up on a microcosm of that.
[Even if you want guns to be "banned" or restricted or whatever, I wish more people could admit that special "gun free" carveouts inside a general population that does have guns is the worst of everything and basically just begging for students to be in these situations.]
If you stop forcing schools to be unarmed, you take away the honeypot target in the first place, and cops can be a little less sensitive now that they know the school isn't a sitting duck any time they miss a clue or are a second late. And the equation changes to where it's a lot harder to get such a rise out of people with a phone call.
(Is there still some window of opportunity to troll the police with fake threats? Sure, but it's less, and the other incentives in play like the chance that you get caught doing it will start to outweigh it.)
There's a lot of "we're talking about restrictions and background checks, not banning guns, relax guys, sheesh" attitude out there in the memes these days. As tho it was so foolish that anyone could have gotten the idea that they want to ban them. Okay, really mean it? Let's extend this to people who happen to be inside of schools. Run them thru the background checks, and then they can arm themselves. Right?
By the by, I'm not sure "alert the news, everyone hunker down" is really the sharpest response here.
You can send in a heightened police presence or investigators, plain clothed officers etc, without announcing it to the world (you can respond without playing perfectly into the trolling).
If the threat is real, you want people to evacuate. (At least, if it's me, I'm gonna way prefer to be gone than be ducking under a table.)
It's a real half-measure of a response. You're not actually accomplishing anything with the "lockdown". If anything, their day to day natural activity seems like it would spread them out more and make a shooting spree less easy. (Seems so hard to justify how "stay in one place, but don't leave" would ever make sense.)
So you perfectly feed the trolling but not in a way that really makes anyone safer.
Why even announce to the threat that you're on guard? Game Theory 101. You should prefer he not know you're on guard so that to whatever extent the threat is real, at least he tries it while you're ready for him, rather than he knows to wait a couple weeks and do it while you're not looking.
(You should be on guard without necessarily making it known that you're on guard.)
I'd imagine the thinking is something like "ok, let's put the word out there so that it's known we're responding to it and aren't on the hook for ignoring the threat". They want the perception of acting on it (to cover their own liabilities or perceived liabilities) more than they necessarily want to act on it in the most effective or logical way.
Weird incentives that happen when everyone is so emotional and media-driven.