First off please don't flame, but just incase I'm zipping up the suit.
Our old school system had hard and fast rules regarding taking kids out for vacation. A letter would come home with the school calander, their position was the parents didn't apprciate nor respect the job the teachers did.
I had become very friendly with one of the teachers and asked her about it and she said to me "most teachers when asked if it matters if I take my child out for a week was viewed as an insult, she said, what do parents think we do all day play games, yes it matters." Her words not mine.
Now, me I don't think it's a big deal if they miss 1 or 2 days, but I'd never take my kids and have them miss an entire week. But that's just me.