I think they also ask those great open-ended questions to by time and jog their memory. :-)

Honestly, I think the good ones have learned and trained themselves how to focus and listen. When you do this you can remember a lot of details. My T also does not try to multi-task during the session.

I also noticed that sometimes my T doesn't always remember the details. However, she appears focused, interested, and is a good communicator; so she simply asks me to refresh her memory when something is fuzzy. I don't mind doing it, she is only human.