I haven't been a UM for a long time, but I fly through TLV a lot As with anyone else, I think they'll want to be comfortable with understanding who she is and why she's flying. There's obviously some risk of people placing something dangerous with a flying UM.

I suspect that most of the questioning will be directed at you, not her, and I doubt that the agents will be unpleasant and interrogative to a child. That said, I might tell her in advance that the folks might ask a lot of questions to help keep her safe, and that she should answer any directly and truthfully.

I wouldn't worry about it much.