It would seem that the tendency to have their mind wander off is probably directly proportional to how the sessions go. I mean, if there is good back and forth and active discussion going on, it is hard to drift off. But if they are just sitting there listening to a client talk the whole time without much interaction, I would think the tendency to drift off a bit would be easier.

If I'm in the classroom actively interacting with my class or tutoring a student directly, I have no problem staying 100% focused on them. That's how I keep my "stuff" at bay at work. However, if the class is taking a test or quietly writing an essay, that is the point where my "stuff" has the opportunity to drift into my classroom.

I would think that same tendency would be there and that T's would need much self-discipline and skill to stay present if their role is fairly passive in a session. I don't have those kind of sessions though. Ours are always more of a conversation, so I can only really quess at this. Actually, all we can do is guess about this since we can't read what is going on in our T's heads unless we actually ask them.