If the kids can't go during the summer, take them during Christmas Week or Thanksgiving Week when the kids have breaks? Oh wait, it's crowded then
So - what's your point?
It's a teacher's job to teach. I don't think the parents should necessarily expect them to do MORE work so that they can take their child out of school.
I think it's the parent's job to make sure their child is prepared to learn, and that they complete assignments as necessary. And if their child needs extra help, a responsible parent makes sure they get it (either by them, or some other manner).
I know there are parents who have strong opinions about what goes on in the classroom, and what they think should go on there. I'm sure a lot of teachers would like to say "as long as I teach what I'm supposed to teach, don't tell me how to teach". By the same token, if the child keeps up on their work, and doesn't fall behind their class, I don't think their family's decisions are any of their business either.
I'm taking my DGS (7) December 12-20. He's going to be out of school for 6-7 days. He's a bright boy, he's ahead of his class, and he'll catch up with any homework over Christmas (his teacher isn't concerned).
Why are we going at that time? Because I wanted to go at Christmas. Because I wanted to go when it was cheaper. Because I wanted to go when it wasn't crowded.
If he falls behind in his school work, or doesn't seem to be able to learn because he's been out - object. If your school board has a rule that doesn't allow it - raise that (and we'll get around to changing the school board). Otherwise, my reasons are none of your business. So what if I don't want to pay more & deal with crowds? That's between his mother and me. If he's not prepared for his school work, then you can chime in.
After all, no one listens to her when you teach her children stuff that is pointless, politically correct, and just plain WRONG.