The way I usually do it is to make a tarball of each users enviroment and
then when they log out of X I have it delete any config files and restore
them from the tarball. The nice thing about this solution is that it
doesn't upset software that freaks out if it can't change it's own config
file and it works regardless as to Gnome, KDE, etc.

> I'm just thinking back to my days as a high school computer lab admin.
>  My biggest problem was preventing the kids from screwing up the desktop
> environment.  I know it made me look like a grump complaining about new
> backgrounds, but it made it much easier to tell at a glance when a
> machine had been altered if all the desktops shared the same setups.  Is
> there any way block user modifications to the desktop with KDE?  I've
> never used GNOME.