Protect them how? From viruses? From Trojans? From Worms? From Hackers? From Malware? From Ads? From SPAM? From Phishing sites? From Pornography? From Predators?
Well, the first 3 - 5 of them are covered because Zonbu OS is a distro of Linux. Linux does not run any of the 150,000 viruses that are made for Windows. There are very, very few viruses written for Linux. And the vast majority of the viruses "in the wild" meaning out on the Internet waiting for a victim, are for Windows only. Linux is just about as safe as Mac in that regard.
Hackers - if your network has a firewall, (and it should!) then you are protected no matter what the computers on the inside are like.
Malware (Spyware, adware) are programs that say they do one thing, and then do something else completely. Like they say they are a game, but they are really spying on everything you do on your computer. Again, these are 99.99% of the time written for Windows, and just like any other Windows program, will not run on Linux.* Also - Zonbu is a "walled garden" - meaning nobody can install anything except Zonbu. As long as they are running the OS that comes with the hardware - you're safe.
Firefox is installed by default, and Firefox has Ad Block Plus, which can easily be installed (Firefox extensions can be installed on Zonbu - that's about it), so the kids can be "protected" from Ads. There are also things that can be installed to look for phishing sites. However, that's more of a Network Admin thing than a end user terminal thing. In other words - if your part-time network guy sets up the entire network to block certain things (porn, myspace, phishing sites, facebook, etc.) then it won't matter what computers you use. Tell him to check out OpenDNS if he doesn't know about it already.
Protecting them from predators will be the most difficult, unless you block all social networking sites and instant messenger programs. (Zonbu comes with IM software pre-installed, and just like you can't install software - you can't remove software either.) But it is possible, I believe, to block the traffic, even if the software is there.
SPAM can be filtered out by whatever email service you use, but if the kids are going to have a computer that is "theirs" then Zonbu has an email client that can also filter SPAM.
I believe, also, that the Firefox on Zonbu has a content filter pre-installed, so you can filter porn/ads/myspace/etc. on a desktop-by-desktop basis - but it's easier, IMHO, to just block it on a network-wide basis. You could always do both - but if the guy is part-time and wants to keep things simple - network-wide is best.
If, somehow, one of your 733T students hacks the computer, or messes it up - whether on purpose or by accident - the great thing about Zonbu is that they can restore your computer to the latest release of the OS / software very easily. All the software will be there, just like when you bought it new (except with the latest release of all the software). That's another thing too that's great about the Zonbu system, especially for someone with a part time IT guy - the system updates itself. Worst case scenario he'd need to restart the systems once or twice a month to makes sure they are up to date.
Hope that helps.
(BTW, I don't work for Zonbu, in case, people have accused me of "Flaming" Zonbu on the forums. I'm just sharing my own opinion based on my own experience with a Zonbu Desktop.)
* There are ways to run Windows programs on Linux, and some programs are written for both OSes - but Malware / viruses are not written for both - and Zonbu can't run any Windows programs.