Rob I am finally back on track with you....except for the trip thing.
It is our family XMAS tradition with our kids. Would you honestly take your kids away from their mother at XMAS and at the same time remove their mother from their annual vacation?
You may, but I won't, knowing how much it means to them.
Let's just agree to disagree on this one and the money thing which is already done, and move on. Even if they are "wrong", 2 things are going to be the ultimate in final outcome.