A public classroom is not exactly a public setting. I don't even know how you can equate these 2 things. As if a public school means anyone can just walk in because it's "Public" No teacher from public school should have any expectation of complete privacy of what they teach the students, I don't know what makes you think they ever did. Sure some leftist run schools are getting away with it, but they are breaking the rules. Everything they teach should be known, and communicated to any parent who asks.

If you want all students to be recorded, video, and audio at all times then you should just home school your kids, because that's ridiculous. IMO you'll create students who are conditioned to accept all forms of surveillance and authoritarianism.