School Optional?

When did school become optional?  A place that's there "if you feel like going" but if not, no worries.  We are so lucky here in Canada that we can safely go to school every day, girls and boys, brown, white or purple, without fear of being attacked for wanting an education.  And yet....  I see kids all the time who show up when they feel like it.  I teach little kids, so they are not making these choices on their own, they are making them with parental support.  Some of my neediest kids, the kids who absolutely should NOT miss a moment, are of the "come when you feel" crowd.  What am I supposed to do then?  They are already so behind, missing so many pieces of the puzzle, starting on the second floor trying to build a base, and then they wander in and out!  To me, this is unacceptable.  But maybe there are other things going on.  Who knows what these kids and their families are facing every day at home.  I try to remind myself of this.  But at the same time I just feel so helpless when it comes to trying to educate them.  Education is such a privilege, and we have the right to it, and I am there just waiting and wanting to help...  So please, send your children to school!  2 month vacations in the middle of the school year are not okay!  Wandering in late, or after lunch, or missing at least one day a week is not okay!  I guess all I can do, as the teacher, is hope and work with what I've got...