I am kind of surprised that no one mentioned the simplest solution of them all... Remove the
power cord! If the school procedure is to
call in the tech staff for events that need lighting beyond the
preset panels then you can just store the
power cord elsewhere and pull it out when you need it. For that matter, you could probably put it in a cabinet in the booth where you store other stuff and no one would even bother to look if they didn't know it was there!
That being said, there is little that one can do these days to really mess up the
console unless people are coming in with hammers and bashing on it. Pushing around faders and punching in channels wont mess things up. Neither will writing a few cues or subs unless you haven't saved your show. They might mess up your show file or submasters, but you should have a backup of those anyway! If you aren't saving your shows to both the internal drive and a flash drive, you should start doing that yesterday. That way if you
walk in an someone has changes your settings or show, you can just re-load it and go. The show files saves most (if not all) your show AND
system settings, so save early and save often.
I believe it has been mentioned, and despite the fact that you have been working with school administration, it is still a public school and a public building. You can set up policy until your ears turn blue, but odds are if some teacher asks for access, or if someone books the
auditorium for an event and doesn't want student tech staff, they will get what they want. If you disable things to a
point where that rental can't do what they contracted for, you or your supervisor will probably get some angry phone calls and some form of reprimand. For any
cover or lock box you put in, you will probably need to supply a good handful of people with keys, including custodial, so while you may limit access most of the time, it won't work always.
You will find that we say something to the
effect of the following all the time here on CB. It is high school
theatre, right now you have a strong
theatre program with good technicians, but in 3-5 years, the school might not. Those middle school kids may be the people running things, or there may be only one semi interested kid. Ultimately at some
point someone is going to end up learning how to use the systems and gear by sitting down in front of it and playing. It won't matter if you train kinds or teachers or if you write a tech bible like many students try to do. You don't really have to provide full on
console training for every student or teacher who is going to use the
system. First of all, you can't, no matter what you think you know, or how good a
programmer you think you are, you are not a trainer and you don't really know as much as you think. That goes for almost all of us professionals as well. There is a big difference between what we can teach and what a trainer can teach, and believe me, I still
call my college professors,
console trainers and friends at the manufacturers when I have questions. However, you should provide basic training to anyone who may need to use the
system. Walk people through how to turn on the
system, turn the lights on, use the submasters, and hopefully not overwrite your
current show. It really only takes about a half hour to teach someone the bare-bones of turning lights on using the
console, that there is no reason not to ensure that any potential user knows how to do it. Even train the middle school choir director. It is also something that you can put on a single
page cheat-sheet that you can leave at the
console for reference by users. This should give you more peace of mind.
i didnt think of the keyed 
