At 10/11, if Bball is important to them and it is possible to do an alternative trip (post vs pre land), I think they will resent not being at Bball. I would not want to start a big trip with any shadow on it. Plus, the dynamics of a divorced family have lots of give and take. This is one time that I would "give." And, yes, I have been in that position before. DH and I stood our ground for certain things, but "gave" a lot to keep things calm for DSS. Now, DSS is 30, no regrets on any of those "gives," and some were really big ones--like what high school DSS went to.