It doesn't seem likely that there's a way to prevent the printer settings from being changed/saved/ They are a user preference, the user is allowed to set them.
Think the way around this might be to give people who use the computers often their own accounts. It would be nice if you could create an account once and use it on all the computers, and it would contain the same files and settings whenever you logged in. Then we could just have a guest account for everyone else, and the files and settings of this account could be restored from a master copy every time it logs in. This requires the server though. In the meantime people who use them a lot can setup accounts for themselves on individual machines.
I've had it with you. If I had an image of a laser gun I would absolutely position it right here in my hand...
Ha! I have a real laser absolutely positioned in my hand!