I teach in a school in an impoverished area (all the students in the entire town receive free breakfast and lunch, regardless of parental income). My school (which is its own district) will not accept parent notes for absences. Doctor notes, funeral home notices along with proof of relation to student, subpoena (as long as the student is not the defendant), college visits with proof from the college, etc. We have recently changed our unexcused absence policy from 5 allowed per quarter to 4 (which is still excessive to me).
Many of our students are expected to translate for relatives when relatives have doctor appointments, so they must miss school. They are also often expected to care for younger siblings (or their own children) when the kids are too sick to go to day care. Last year, I had a student who missed 33 days because she was the family's representative at an overseas funeral.
Of course, none of these absences are excused.