I'm hoping if I explain what I'm wanting to do here someone will have a suggestion. We have a Mac classroom for students to use with 30 iMacs and one instructor computer (a Macbook) up at the front. All of the computers have the same two logins on them - a student login with parental controls enabled and password protected, and an admin login (which we don't give out the password to for obvious reasons). We WANT the instructor station to be able to share the student's screens. This part was easy because with all the passwords being the same, the instructor only has one password to remember to get access to all the computers. However, we DON'T want any outgoing screen share requests from the student stations. This brings me to the problem that no matter how we implore the instructors to not give out the password to the students it somehow leaks out eventually. Then we have students sharing each other's screens and everything rapidly goes you know where in a handbasket. So I'm wondering if there's a way to disable, cripple or maim screen sharing on the student stations to the point that they can't initiate outgoing connections but the instructor can still initiate incoming ones. Third party software unfortunately isn't an option for us.