Child porn laws, like any laws, should be enforced without respect for the defendant's status. If the definition of child porn is so broad as to include what this school has done, then they should be prosecuted as mercilessly as anyone else would be.
I think it depends on what the intent was. If the intent was to surreptitious take pictures of minors with the hopes of catching some nudity, then I'm guess it falls into the CP bucket.
I think it would be hard to show though that there could be a different intent though for surreptitiously taking photos of teens at random times.
A big part of my job is proving intent in just such cases. It is, as you point touch on, really difficult.
There could be a very "innocent" reason; the sysadmin could be simply obbsessed or interested in individuals lives (it's actually not an uncommon problem) and not even consider that something indecent might appear on screen. She might not find it sexually interesting etc.
If the intent really was to photograph nude children then I'd fully expect there to be lots and lots of evidence showing this (particularly in terms of other indecent material on her computers).
Supposing intent was not CP, but was some kind voyeuristic intent, what are the possible kinds of ways she could be prosecuted? What about the administration of the school who signed off on this debacle (particularly the forced use of the laptops under penalty of expulsion that contributed greatly to this mess?)
