Oh yes, I am constantly on the lookout for these little body language cues not just in therapy but especially so in it because of the intimate setting. I think Ts have been trained to be aware of this sort of thing but of course they slip up at times. I've caught my ex-T blinking reaaaal slow a few times (like over the span of 3 s) while smiling inanely so it's led me to believe she's on the verge of dozing off. Fortunately she doesn't do this often and when I tell her something important she usually leans forwards and furrows her brow, or forces a smile/laugh because that's normally what I do (in awkwardness) so it sets me more at ease. I suppose conscious efforts to look more engaged on her part will be more effective on someone not focusing on the presumed intent behind her actions, but I'm over-analytical by nature and sometimes it feels contrived to me. But of course that's just my own weird thinking and it is on the whole better for the T to actively present positive body language.