How, exactly were you advising someone to login to that all powerful account? At least where I go to school, they don't really have it all that easy to find out which account it is that manages the proxy server, and also, you wouldn't know the password. Now, if you were able to crack the password, and get into the proxy, besides having to know a fair amount about how the proxy operated, so you could know where exactly you had to go to access the management for it, what happens when you said the Proxy server would have to be restarted? If the Proxy itself was the only thing restarted, it wouldn't be so bad. But, if you restarted the entire server, that would be pretty noticable.
But, anyway, that's beside the point. I don't know how well they monitor things at my school, but I do know, at least, at another local school which I work for, they do a pretty good job logging EVERYTHING that takes place throughout the day, and who did it. Irreguardless what account you used, they would still know that someone had tampered with the system, and could more then likely trace that tampering back to the exact computer you were using at the exact time it was done.
Knowing that, all they would have to do, is find out who was in that classroom, and whether or not the teacher or whoever may have been in that room knew who was at which computer, they do know who is supposed to be in which classroom at what time. Even if they didn't, they have cameras near every classroom, and in a few cases, one in a few computer rooms.
I know when someone got into a teachers account at the school I work for, that teacher had been given special rights to create and manage users. Now, that kid that got into the account made himself a new account with full privilages, and messed a lot of other students access rights. During the same basic time, the blocker on the proxy server had been either shutdown, or something, because it wasn't working anymore. Now, I don't think it was found that the student had anything to do with the blocker. But, that's beside the point. They have things monitored so well, that they easily found out who it was and expelled them.
Now, when we had to get the blocker back up and running, the proxys had to be unloaded. At least with their systems, you have to know a lot about how Novelll works. Or, at least how to unload services, which, I guess, isn't too bad, if you know what you're doing. But, it still in some cases, requires either having physical access to the server, or the access rights, and the correct program to remotely access the server.
As for my school, I don't know how they run anything in the schools network. All I do know is that they seem to be running Windows 2000 Server addition, and some login script. I forget what it's called, though. Our tech guy for my school probably isn't the smartest for operating networks though.
It would be easy to gain access to the admin account on our local computers at school if they didn't have "Deep Freeze," if anyone knows what that is. It's a program that basically takes a snapshot of what data is on a drive, and when you restart the computer, it restores the computer back to that. Thus, any changes are gone. So, even providing that I do have a disk that allows you to change the Admin password for NT based systems, once you restart to login to windows, that is gone too.
Dontcha love those things? I haven't yet found a way to get rid of that program on NT. I can on 9x, but we don't use 9x.
EDIT: forgot to address this:
ALL proxy servers that operate for schools are ran by counties, not cities (with the exception of metropolitans).
I don't know for sure, but as far as I know, at least one of the schools I go to manages their own proxy from their own school. Not through any county things. They just have this T1 line that comes in, at the Admin building for the school, they have one central proxy server, which is dedicated, I believe, that filters out all the traffic, then, each individual school has two servers. One server is the basic file and authentication server, and the second acts mainly as a proxy server, and also will authenticate you. Then, each school's proxy server then ties back to that central proxy via T1 lines.