If the student was installing it on a classroom PC then the teacher/school sucks at securing their network and workstations.

If the classes curriculum is Windows then the kid needs to be working in windows. So yeah, give him detention.
If he wants a different course of study he should lobby for it. Or start a Linux club at his school.
I hate M/S operating systems and always have. But the fact is it's what the business world is using.

I have the feeling this kid is probably one of those obnoxious ubergeeks who preach the same religious platform nonsense that a lot of Apple/MS/Linux/Oracle fanatics do.

I also have the feeling that this teacher would advocate the "flat earth" doctrine were it the district policy.
Even if you took her up in the space shuttle and let her see for herself.