FWIW, for those who are triggered by erotic transference, I think it is entirely possible to be aroused in a session without being aroused by a therapist. A lot of times, subject matter is inherently arousing. Or I find that being extremely anxious (or a bit hypomanic) causes a physiological reaction of arousal that has nothing to do with the person I'm with. I note the physical reaction merely as a clue to how I'm feeling. If my therapist notes any signs of a physical reaction, he is well aware of my tendencies, and I'm sure merely notes it as a clue to how I'm feeling.

Since I experience the same thing no matter where I am or who I'm with, I don't connect it in any way with attraction to my therapist. It also doesn't remotely depend on his person or his actions. For example, a smile or look from him doesn't increase the response.

My therapist says the anxiety/physiological arousal link isn't a very common reaction, but that it certainly isn't unknown. He gave me a few examples. (Not involving him of course.)