Collective punishment
Why would you even vaguely consider grounding your daughter for this? This is pure unadulterated awesomeness.

It is also (as I understand it) true.
Students are considered civilians and therefore considered protected persons, under the 1949 Geneva Conventions, collective punishment is a war crime.
Article 33: Individual responsibility, collective penalties, pillage and reprisals
- No protected person may be punished for an offense he or she has not personally committed. Collective penalties and likewise all measures of intimidation or of terrorism are prohibited.