I'll be taking my son, in grade 1, out for two weeks in Feb. Ok, it's only gr 1. The school has already circulated its policy, which is it does not give out work packages beforehand, but will keep the worksheets, etc., to give kids on their return.
Not perfect, but as a former teacher, I can live with it. Choices and consequences, as we tell ds all the time! ;-)
My son's teacher has TWENTY EIGHT kids. No aide, no nuthin'. For me to ask her for that work before hand would be presumptuous. Yep, she's an experienced teacher, a really wonderful teacher, but it's her first year at our school, maybe her first year in gr 1, and I know the work often ISN'T fine-tuned a couple of weeks ahead. I don't want her to have to dig out the worksheets from last year or whatever.
The usual school faculty will have a lot of experienced teachers who may well have everything ready to go, but there will be some in the mix who are young and less experienced, some who have taken on a new course or grade for a professional challenge, and others who just revise every time they teach something--which is a blessing for the students, rather than getting an assignment that's been used verbatim for years.
I taught high school and I know you can cover a LOT in a week or more, especially in Ontario where classes are semestered. (I.e., you have course X for 70 mins a day every day but are finished it in one semester.) But our school did support family vacations and wouldn't say no. I think you just have to understand that thing about choices and consequences--and of course make sure older children understand too.
For younger ones, I think parents can do a lot to support the learning, make the vacation relevant. (Last May my son did a journal, as others have mentioned--great for someone learning to read and write!) Older ones too--not just the obvious stuff like, oh I don't know, a little zoology at the Animal Kingdom--but the extracurricular intangibles like being comfortable in another country and culture (they speak English, I know, but it's not Barrie!!), or even the sophistication to negotiate a busy airport, or get through Customs. However, I have to admit, with sinking heart, once the kids are in high school, I won't take them out for more than a few days for a family trip. (Some days I miss teaching, but not when I look at the cost of travel during July and August!)
It's unfortunate when schools or boards are less than diplomatic in communicating policies, as was the OP's school apparently. I would guess their INTENT was to make sure everyone had thought about the consequences of the planned absence, rather than putting any individual family through the wringer.
All that said, I don't think 4 days would be a huge deal, as long as it's not during exams or something.