I wonder if some of the controversy about this topic is due to the fact that the destination is Walt Disney World. Couple that with the fact there are quite a few folks on the boards who venture to WDW more than once in a years time, it seems such travel could result in quite a few instances of extended absences from school. Although WDW has educational aspects, that is not the primary reason why my daughter and I vacation there, and I'd hazard that for most folks/families the draw is the FUN and not WDWs educational opportunities. IMO, the positioning of the educational aspects of WDW can get a bit over the top (not in this thread, but in others Ive read).
For the record, I did pull my daughter out of school for travel to WDW, once in 1st grade and again in 3rd grade, but it was work-related (I had conferences to attend) not personal vacation time. At that time, the absences were excused. Fast-forward a few years and to a completely different environment in which family vacations would be marked as unexcused. She is now in middle school (7th grade) at a private school with a heavy focus on math and science, and although there is greater flexibility than with the public school, she would miss far too much. We are fortunate to be able to vacation at WDW each year (in June or August), but even if we werent, I would no longer pull her out of school for travel to WDW. The same thinking will apply to high school as well.
However, if we are talking about travel to a foreign destination (my work requires travel to 3-4 conferences a year, sometimes to foreign locales), then I would most likely pull her out of school and work with her teachers and the administration accordingly. So, I would pull my daughter out of school for the up to the 10-day unexcused absence to go to Rome but I would not do so just to visit the Italy pavilion in EPCOT.