Monitoring for sex offenders and visible weapons is not necessarily that big of a deal. Not like they will actually have many incidents of that, if any. What is most concerning is once a student's image gets uploaded into the database. I don't know how accurate their facial recognition is, but if combined with motion tracking, you have an extreme potential for abuse once a student's image is uploaded for whatever reason.
Say a student's image is uploaded because they're going to be suspended. Possibly it wasn't even their fault, whatever they did. Then they track them for the last 60 days, and write up every single possible infraction, and decide to expel them. Were they deserving of being expelled? Perhaps. I dunno, it's a hypothetical. However, they are deserving of an education, no matter what. Then they have to transfer to another school, putting undue hardship on them.
And what happens if there's a data breach? These students are being recorded all hours of the day. There is no way that something isn't going to happen that wouldn't be of interest to some pervert somewhere. I somehow doubt that they will be following all necessary security measures to ensure no video ever gets out. Hell, they even admitted that they had used video of the students, without their permission, while developing the software. I doubt they were paid, despite taking a role in the development of commercial software.
I didn't even have to get into the possibilities of overreaching government. It's already disturbing enough, just with what they proposed and admitted to.