A RAD moment?

I think I am in a situation where I know just enough about a subject to be dangerous with it. Not enough to actually be helpful.
When we got here to visit with the girls grandparents, The Husbands parents, my MIL asked the girls right away if they wanted to spend the night at their house. Both girls said yes right away, Genea said it first. That was a shock to me! I knew the grandparents wanted the girls to stay over (and of course I thought that was a great idea) but I expected them to take a day or so to settle in. Especially Genea. Obviously.
My first thought was, oh shit! What's wrong with this picture? This cannot be good. Genea hates new everything. While I prepped up the girls something crazy for this trip, no one gets in with Genea that quickly. No amount of prep could have made her feel comfortable right away like this.
What if it was a RAD moment? RAD is Reactive Attachment Disorder, and many children who were adopted older or had multiple caregivers, are diagnosed with this. One of the points of this disorder is that the child will go to anyone, can be overly friendly, and will go to strangers as if they were family. The adopted family is shunned, pushed away by the child out of fear of abandonment and takes the brunt of the child's fear and anger. The childs behavior can be outrageous and extremely hard to manage. We have that.
What if all this time, when it looked like Genea had bonded to us all, she really only came to us out of her fear. Maybe she holds on to us because we are the only people available? Too scared of another new house, maybe she has been play acting the togetherness. When she hugs and kisses and says I love you, is it because that is what we expect and not what she is thinking or feeling? She knows her Grandma K from probably 3 separate week long visits over the past year and a half. That is not enough for Genea to go right to her and spend the night! I mean, I am happy she loves her Grandma but this is a strange behavior for Genea.
My only possible explanation is this--- we told the girls we were going to visit their grandparents house. Every turn of the trip they thought they would land on their doorstep. Instead we took a cab to the airport, took 2 separate airplanes, a bus and a van. We kept going places and none of them resulted in their grandparents house appearing. Grandma K met us at our hotel when we arrived. Not her house. And just maybe, Genea had in her head, Grandma K's house, and the events were not completed until she was at the actual house. Like, such concrete thinking that she would only be able to relax when she was at the house standing in the kitchen.
I hope that is it. That she just had to finish in her mind where we were supposed to go. One thing her therapists have said many times is they were always worried that Genea had such an ability to change herself into what was expected of her, or what she perceived other people wanted. A chameleon, is what they said.