I am sorry the talk didn't turn out how you had hoped.
I hope you don't get upset with me and I am sorry if you do but I really do think you are making a very grave mistake even using the words "flight risk" with your W.
She told you that either way she is about to get her attny involved. If the two of you can't agree together about the passport/taking the kids out of the country issue she will have to tell her attny that. She will also tell her attny that you told her the concerns you have about her being a flight risk.
In turn, her attny is going to start protecting HER so she can do what SHE wants when SHE has custody post divorce and don't think for a minute those wheels won't be in motion before you know about it.
I know it's so hard. I know you want to grab your W and shake her (I am not implying you are violent, I just get the frustration) but there are some things you are going to have to keep to yourself in the legal sense. If you don't it will be YOU that adds to the legal bills because your W knows ahead of time what is on your mind and don't think for a second she won't be telling her counsel all of it.
By telling her you feel she is a flight risk (and I agree that she is) you essentially spilled a potential legal strategy you could have used to your benefit to the "enemy".
I tried to make this post more gentle and I am sorry if makes you more sad but I made SO many mistakes trying to talk to my H and all it did was hurt me and my case more.
