I'm a certified teacher at both the Elementary and High School levels, both my parents are school Principals, and I find this situation repugnant. One of the most prevalent problems in schools is the lack of good home-based mentorship (particularly from dads). I've had native Indian boys leave school for 3 weeks to go moose hunting with their grandfathers, and the positive change in their behaviour and academic results upon return is remarkable.
This is worth fighting for. I can understand individual teachers being hard-headed or lazy about the situation, but if the school principal (or Dean) is actually going to penalize a student for experiencing a wholesome family activity, someone needs to lose a job. Any idea how many of my former students went away on sailboat excursions, trips to Florida, overseas tourism, etc? I promise you those things add more to a kid's life than a week of academics. That's the reason I quit teaching...stupid secular humanist Socialists in their self-righteous positions protected by unions. I would go to war with this school, no doubt!