I think that this is a very kind gesture on her part. She might also want to do it to get more of a sense of who you are and see you in your "natural habitat." Yalom talks about doing this in his book The Gift of Therapy. I think it'd be neat to have my T over. I think it would be harder to get into "therapy mode," but I'm sure it'd be fine after a few minutes.

Of course, if you are not comfortable with this, then you don't need to do this. You can set/keep your boundaries. However, I think it would be interesting and different for both of you!