Mission feedback

I've been jogging an idea for a mission that I'm not sure how exactly it would work out, the goal was to make it heavily reliant on participant decisions and character interaction while having a sufficient amount of net battling.

Basically the idea was for a participant to be hired as a teacher for an advanced net battling class, essentially a 5 day (plot wise) Mission that involves a more higher leveled player training a group of medium grade young students within a school. The class would have about 5 or 7 students each with a navi that statistically are around lvl 7. The task of the participant was to educate these students in advanced net battling with the IC experience that operator has, and on the 5th day test them all to give them a final grade. Now the "Teacher" would be given a study plan to get an idea on what to do, but how it's done is up to them.

Their students would each be a unique character with their own navi, and would actually develop as the mission goes on, at first they would be somewhat mediocre as netbattlers but depending on how the teacher carries the class may improve to some degree, and how well they improve is what determines the reward at the end of the mission. The goal behind this mission was to involve quite a bit of NPC interaction between the player and a set of different character archetypes, it would be something of a challenge for not only the participant but for me as a mod.

Aside from deciding how the mission would flow, my one problem is that while the mission would be rather free form, there are things I absolutely do not want participants to do, one of those being to wantonly assault all the students and/or their navi's indiscriminately or try to completely hijack the established goal of the mission. while I could just as soon deem it as auto failing the mission, but that may make me look bad as a mod.

So basically I wanted to ask for some feedback on the idea, maybe some insight on how it could work out, and probably ways to avoid plot derailing, which is something that we mods apparently cannot punish but at this point I have no real way of restricting that in context.
Here's the thing about plot derailing: you have to be prepared to let the participant fail at their goal. Nothing is guaranteed in a mission -- if a teacher indiscriminately attacks their students, you can bet your narrow ass they wouldn't get their regular pay. Just ride it out as normal, play out the consequences, and when they report in for their mission reward tell them that no, that was not an acceptable lesson plan.

The mission itself? I probably would do something to derail it, just because that's my character and (much like the mission that I can see influenced you when writing this) it all sounds potentially rather slow and gruelling at this point. That's another factor you have to think of. Adaptability is the watchword for a mission mod, and so you need to determine the consequences as events warrant. Sometimes, this'll mean you don't give the player their reward, but odds are they came into the mission knowing full well that if they moved completely contrary to its goals they wouldn't be walking out with a prize.

You're correct, though, in assuming that you shouldn't accomplish this via spontaneous death for everyone involved. Consequences should follow logically from the actions the player takes. If that means taking a mission in a new direction, well, think on your feet.
You may also decide to divide the mission up into sections, with breaks in between the school semester for the player to go off and do their own thing before coming back and seeing how the NPC students evolved.

Although having multiple smaller missions may work out instead of one long mission with breaks. Perhaps with a different or returning player for each class.