I think you might be assuming that a T actually knows that you are going through transference, which I think is a lot to assume because transference is based (at least I think) on your feelings. If you hide your feelings (I'm pretty good at it) and/or don't let your T know what you're feeling, then I'm not sure there's any way they can possibly know. They might be able to observe that every time a certain dynamic appears in session, you seem to be experiencing some kind of change in emotion, but they can't necessarily identify what you're feeling or what's going on with you if you don't clue them in. Some T's probably need more cluing in than others.