First off - yes, this is very illegal which is why you don't see the use of active jamming equipment in the US. If they want to instead build a Faraday cage around the entire campus, this would be the "legal" - though prohibitively expensive - way of getting around the issue.

If in fact they attempt this, and staff or a student have a bona-fide medical emergency and are unable to summon emergency services, this district will then be tasked for paying for a home nurse to wipe the drool off of said victim's face for the rest of their lives.

You would think those who work in education would, you know, educate themselves on the relevant laws and ramifications of actions... nahhh, this is the US public school system we're talking about here.

Yawn, Loopt has been doing this forever.