I think Ad is trying to model clear communication while also trying to convey that she is flexible and willing to work with him if he had plans with the kids.
Which is what she would like in return from him, I believe.
Personally I would have written...
"I am planning a trip with the kids from 7/31 to 8/4. Please let me know if this conflicts with plans you have made with them."
Still friendly but less "unless you tell me no".
Just MO.
"Acceptance doesn't mean resignation. It means understanding that something is what it is and there's got to be a way through it."--Michael J. Fox
