This topic always stirs up a lot of controversy here and there probably is no set answer and district policies vary widely.
I have no problem with districts trying to discourage kids from taking vacations during the school year. After all there are long breaks during the school year and most have at least a couple months in the summer. Of course, it is those breaks where Disney tends to be at its busiest. I believe our district limits vacations to 5 days per school year, which seems quite generous.
I do understand the need for some to take those vacations during the school year due to scheduling conflicts, etc. However, I also don't think its fair to ask teachers to bend over backwards to catch them up. If a kid (and parents) is responsible enough to get assignments ahead of time (and teachers, for the most part, are good about giving them out) and can independently learn the material and make up any tests, etc. on return, that's great. Some kids don't do as well...while its fine for the student to ask questions upon return, the teacher should not be expected to reteach everything.
As a general comment, for those who do this every year...it is much easier to pull a kid for an extended time early in their school years. As each year goes on, it gets more and more difficult. Especially in high schools with block scheduling, missing one week of class is like missing two weeks. For some, its a gap they never recover from.