This is my script with my T. I say I love you and she says I know... (and no, I am not a star wars fan and yes, I created the script) for me it serves a couple purposes. First, it helps me believe/know that she carries my feelings towards her outside of the room, she knows I love her even when we are not together.

Second, the consistency in the response provides comfort in knowing that I will always get the same response, it won't be something that might bother me. The 'I know' doesn't bother me as much as some other responses - Thank you isn't bad. I like 'I know' better. Once she said something else and that bothered me, I don't remember at this time what it was, though.

Finally, we have talked at different times about the internalization of T and interactions with my parts. There is a feeling that sometimes this I love you is actually inwardly directed; the child part to the adult part and the child part doesn't feel believed or hasn't felt believed or heard in the past; so the script is to let the child part know that it is being heard first by T. Once that has occurred, the adult part can mirror T's behavior and be able to provide the sense of being heard to the child part. Some of that conditioning that you are reading about.

I will also say I miss you, and she says I know to that too.... in fact the full script is...

me: I love you
t: I know
me: I miss you (or I will miss you)
t: I know
me: I want you
t: I'm here

sometimes t will add something like, thank you for being you, all of you are welcome here, ect.