I'm always intrigued by these discussions, especially as, where we live (in Canada) funding is not tied to attendance at all. We're rather laissez-faire about school attendance, something which can carry through into university and which drives my mom (a prof) nuts. It's long tradition in some families... my father in law used to pull my husband out for a week every spring to go hunting, just like his dad did with him, back in the 40s.
I took both kids out to vacation during the off season throughout most of their school careers. Both my kids were in the gifted program. One kid was a good student, the other has a learning disability and struggled. Their teachers were uniformly supportive.
In fact, one long winter in middle school, my son's special education support teacher actually tracked me down to ask if we had a vacation planned soon. As it happened, we were planning to take a long weekend and visit Toronto. He was very happy to hear that, saying that the boy needed a break, and he'd been planning to recommend we take him out for a few days.
And when my daughter was in tenth grade she commented to her chemistry teacher that she'd decided not to go to Disney that year, because she didn't want to miss school. He said, "Are you crazy? This is the might be the last year you can do this! Go! Go!" So she changed her mind, and we got in one last school year Disney trip.
Now they're both in university, and the girl is interning in a lab, so we need to work around that. Right now, we're basically just doing late August trips with them. Last year we went to Universal. This year we're visiting my dad, but next year Disney may be a possibility.
Of course, that doesn't mean my husband and I can't run off to Disney by ourselves... and we do!