The whole idea even accepting the core premise is OK to begin with needs to have a similar analysis applied to it that medical tests do: will there be enough false positives, with enough harm caused by them, that this is actually worse than doing nothing? Compared with likelihood of improving an outcome and how bad a failure to intervene is on average, of course.

Given that there's no relevant screening step here and it's just being applied to everyone who happens to be at a place it's truly incredible that such an analysis would shake out in favor of this tech. The false positive rate would have to be vanishingly tiny, and it's simply not plausible that's true. And that would have to be coupled with a pretty low false negative rate, or you'd need an even lower false positive rate to make up for how little good it's doing even when it's not false-positiving.

So I'm sure that analysis was either deliberately never performed, or was and then was ignored and not publicized. So, yes, it's a fraud.

(There's also the fact that as soon as these are known to be present, they'll have little or no effect on the very worst events involving firearms at schools—shooters would just avoid any scheme that involved loitering around with a firearm where the cameras can see them, and count on starting things very soon after arriving—like, once you factor in second order effects, too, there's just no hope for these standing up to real scrutiny)