As a teacher in the public schools sytem, I have several comments:
First, I have no problem with pulling a child out for 2-3 days. The average child will be able to manage the make-up work without undue trouble and will not fall behind. With a quick look-see at the school calendar, you can easily choose vacation weeks that'll incorporate teacher workdays, holidays, etc. so that your family can take a full week vacation without the child missing a full week of school. Since schools across the country have different schedules, this will also allow you to travel at off-peak, less expensive times without the crowds.
Here's what my own children have done this year: one week at WDW, a four-day
Disney cruise, a week in Charleston, a four-day weekend at a fishing cabin in the mountains, a four-day weekend in a beach-front cabin, at least 4 weekend camping trips, and at least 4 out-of-town visiting-family trips. How many days of school did they miss for all that travel? THREE DAYS TOTAL. It can be done.
I think pulling a child out for a week (or more!); however, is too much. The child attends school 180 days per year. That leaves 185 days for family time. I always hear people touting the importance of quality family time when this subject is discussed -- and I agree that it's important. However, I maintain that if a family isn't able to have "quality time" in those 185 days, they aren't likely to discover the secret by pulling the kids out of school for an extra week.
I also think we're over-exaggerating the educational value of a Disney trip. Sure, a person who is actively searching for something of educational value can point out some things: geography comes to mind right away, as does culture. But most kids are going to spend their Disney cruise swimming and playing, and it's hard to justify that as educational. What do more kids see: Disney Dreams or Mexican ruins? On our cruise, my children did study the maps to understand where we'd be traveling (15 minutes), and they learned about dolphins in the dolphin swim (1 hour, not including travel time). It's hard to honestly rationalize a trip as educational because of and hour and 15 minutes! They walked through the streets of the Bahamas, but I can't say that they saw anything beyond the tourist traps. The honest truth is that most of our kids are doing the same things we're doing on vacation: playing and relaxing. There's value in that, but let's not make it into something it's not.
Then there's the make-up work. I've been teaching for 13 years, and I can assure you that THE GREAT MAJORITY of the kids who miss my class for lengthy vacations do not make up the work, regardless of how soon I send the work or how many times I call home. A good percentage do absolutely none of the work, most make some attempt but do not complete everything, and about 10% actually do a good job. Of course, everyone says, "Not my child", and it's very likely that only conscientious parents would choose to answer this question. I'll add that I teach high school, so the workload is more significant than elementary school. In almost every case -- even honors students -- the time away from school has hurt their grade. My class is only 18 weeks long, and there's a state end-of-course test grade that'll go in the child's cumulative folder; if your child is out for one week, that's a significant amount of time. Is the vacation worth the almost-certain cut in grades? That's something only you can answer.
Also, when you reach high school, there's the question of eligibility. A child who's applying for newspaper staff, the basketball team, or the marching band will be asked, "How many days of school did you miss last year?" With lots of other equally qualified applicants, a student with a poor attendance record may be seen as a liability to the cheerleading squad or the student council. This isn't a matter of the coach or teacher juding the value of your family's vacation -- it's a matter of needing to know that he or she can count on every team member to be present on a regular basis. High school sports, for example, run only about two months; if your child is out for a full week, that's going to hurt the team -- the coach has to be concerned with this.
Are teachers going to complain when you say you're taking your child out? Of course not. When you approach the teacher, you've already made your decision -- you're informing, not asking permission. The teacher lives in the real world; she knows that disagreeing with you will make an enemy of you, which will only hurt the child. So the teacher makes up a packet of work that probably doesn't come close to matching what the other students will be doing that week and "calls it even".
In conclusion, again, I have no problem with 2-3 days (for a student who's healthy and not likely to miss many more days); however, I don't think a week or more is a good choice.