You asked what the issue was, and I told you: a reasonable expectation of privacy. 

Just because you're in a public place doesn't mean people can follow you around and video tape what you're doing. If you think otherwise, why don't you try doing it some time and see how long it takes the police to show up.

School classrooms and office areas are funded by the public. Should people be able to go and video tape students, teachers and administration staff without their consent? Of course not! Neither should people be going and video taping what students are doing in their approved clubs, associations and gatherings, without the consent of the school and the students involved.

It's such a basic principle of acceptable behavior in a public space that I'm shocked you don't get it.