It depends on your school district and state. What COULD happen?
-You could be expelled or, more likely, disenrolled.
-The absence could be unexcused, which would mean any work/tests required that week would receive a zero, which could make you fail the class
-In some states, like Texas, the parents can be charged with a crime
-At a private school, you could be asked to leave
Some kids go to schools outside their district, so if they are disenrolled, they might not get back into that school but have to go to the school they are zoned for. If the child is in a magnet or charter school, they could be returned to their zoned school.
I think most often things are not so formal but still have bad consequence. The child isn't favored by the teacher, the child isn't chosen for a sports team ora part in the play, the child loses out on some opportunities. For example, my daughter is trying out for her school play, and try outs are the day BEFORE return from holiday break. The teacher said she would allow 'some' people who can't be there that day to try out the next day, but if a student were to extend the holiday vacation 2-3 days in January, that student will not be in the play (unless it she is a teacher's favorite, then there are no rules). This teacher plays favorites, and when my daughter asks for special consideration, she does not get it. Last year she traveled on Spring Break and came back very very ill and couldn't go to school. The teacher said she couldn't be in the play that they had been practicing all spring.
Nancy