It seems unlikely, somehow, that the 2 events are unrelated.
Also, speaking as a teacher - grades are kept on computers, and, in my district at least, the school server upgrades to the district server regularly; burning the school down would not destroy all of the copies of grades or of discipline records, which are kept on the same computer program.
In 1984 the HS I went too, had the grades stored in multiple locations.
1) Instructors were required to maintain a copy either at the school or at home. It could be paper or on electronic media.
2) A hard copy stored for a year (* at least some times two *) at the school.
3) The computer system that printed out the grades had multiple locations as well.
3a) The schools computer system (* but this was in another admin building for the school admins *)
3b) The electronic back up stored at an offsite location. (* This site also stored other schools as well. *)
3c) The service that printed the grades also had a copy. (* Store electronically for a couple of years to make sure there were no mistakes *)
At the time computers were not the main stream and so they also kept hard copies offsite in long term locations, such as a doc-u-store type place.
Being the type who liked to understand how things worked. I tried to figure out how hard it was to actually change a grade. Not that I needed too, just to think about it. I was at an off-site class which also was the location of the place that stored the back-ups as well. This site had lots of computers and large plexaglass type walls. On one main frame cabinet was hanging a clip board with each school's name and id and password visable to anyone walking by.

The problem was that I was told there were seven copies of the grades. Above you will count 6 unless you count the instructors personal copy as two or the actual copy given/sent to the students. Once I figured out how to do it, I then made a comment to an instructor about the security issue of the clip board.
So, while I understand trying to get into a system, and or trying to just see how it works, I do not nor have I ever supported the idea of destruction. I had access via other people and or myself to all copies I could find. But, never once did I think about destroying them or changing them for myself or others. I also would not have thought of burning a school down.
I guess this is a long winded rant about understanding people being curious about how things work but not being destructive.