I grew up in a poor district where truancy was a huge issue and they had a "zero tolerance policy." Any more than five absences in a semester and it became a law enforcement matter. The literal police got involved, as well as Child Protective Services. It wasn't about kids falling behind academically, it was about preventing actual delinquency. It didn't matter that I was a top student, there was nothing my teachers could do.
Now I live in a rich district where the parents, teachers, administrators, heck even the bus drivers are all on great terms with one another. We talk and text and hang out and they're infinitely flexible. My daughter missed three weeks last year for a Disney trip, a Hawaii trip, and a cruise and it was a complete non-issue.