Enable Remote Management by default

Hi @asultana][/url

So, the first thing I would recommend is looking into either MCX or Configuration Profiles to control access to certain System Preference Panes. Doing this, you can lock the Sharing Pref Pane. Since you mentioned you work in a school, I can't think of any good reason to allow school kids access to the Sharing Preference Pane. The only items located in there are things that will get them into trouble, like renaming the computer, disabling ssh access (remote login), disabling Remote Management, enabling file sharing, etc, etc. All stuff that kids shouldn't be messing with IMHO.

As for enabling Remote Management, there are a few ways you can do this. You can take a look at Apple's page on ARD and the kickstart command for turning it on.
http://support.apple.com/kb/HT2370?viewlocale=en_US&locale=en_US

Also, there are a couple of threads here on JAMFNation that cover how to turn on Remote Management using the information from the above link. Here is one, and there are probably others:
https://jamfnation.jamfsoftware.com/discussion.html?id=5178

Hope the above helps.