My philosophy on this.
Taking the kids out of school for a week for a family vacation is the parents' choice, not the school systems. If it's longer than a week, then the parents really need to think twice about it. As the bloke from the UK mentioned, an overseas trip could be a valid reason to take them out of school for more than a week.
No fibbing allowed. Besides being wrong and setting a horrible example for the kids, this puts the child in a really bad spot of having to cover up for the parent when they get back to school. Parents are adults, teachers are adults, principals are adults. Act like it, and be honest with all thing concerning education.
Teachers are dedicated pros and I respect that. But respect is a two way street, and they must also respect the values and decisions of the parents.
If teachers don't give the child work to take with them on vacation, or don't allow makeup when they get, or penalize them for either, then go to the principal. If that fails, go to the school board.
I could go on and on discussing the matter of teacher "in-service" days, a concept that didn't exist when I went to school. But i'll just say that I would find it hypocritcal of a teacher to say it's wrong of the parent to take the child out of school for a planned vacation, but it's not wrong for the teacher to keep the kids out of school for planned in-service days.
-Shawn