They are manipulating your D by telling her about a trip that they want to take her on before running it by you.
I agree with Anvilhead. No is a great answer.
I think it's more than generous to begin with that you send your D off with your ex MIL anyway. If she cant be happy with what you are offering, then too bad for her.
Do what is best for your D. Undoubtedly the MIL will be pissed and that's on her. You are looking out for your D.