First off, let me say that I am a parent that has taken my kids out of school twice to go to Disney...once when daughter was in 1st grade (son not in school yet) and again when daughter was in 3rd, son in kindergarten. I gave their teachers 4+ weeks notice, asked them to put together work packets so they could keep up, and faithfully made sure that the packets were done the day the kids returned to school. It was a no-brainer to allow them to miss school at these ages to avoid crowds as I knew I could easily help them stay current with their work.
However, now that my daughter is entering HS and my son about to enter 6th grade, there is absolutely no way I'd consider taking them out of class for a vacation, plain and simple. Aside from the fact that their workload has increased, there are now rules in the upper grades about the total number of absences allowed before automatic reductions in grades occur. Those automatic reductions can occur even if the absence is due to illness.
I could never turn a note like that into a teacher with a straight face. Are their educational opportunities available there? Yes, no doubt. But in reality these trips are vacations, plain and simple, and you are choosing to go during school. These are not one-time seminars that are only held while school is in session; Disney is open all year and your children can get those educational opportunities in the summer.
There will always be parents who take their kids out to go in the 'off-season', but to try and disguise a Disney vacation as an educational opportunity to avoid an unexcused absence is sending the wrong message.
Just my $0.02.