Not precisely a boundary violation, but boundary related — it’s always helped me when therapists are willing to outline exactly what their legal responsibilities are. For example: when they are required to contact medical personnel. This makes it easier to discuss certain topics without worrying about medical interference.
That makes a lot of sense.
I don’t know how much what they say matches what they do, though. Do you know?

well, i’ve seen psychologists on and off since I was a kid and was even studying to be one so i can say with absolute certainty there is a very strict code of ethics psychs are expected to abide by. I can also say with absolute certainty that this high standard in practice virtually never happens in reality and I haven’t met a single person who *hasn’t* had a psychologist breach confidentiality with such severity that if it was reported they could lose their license to practice. 

I don’t know where the real lines are. But I do know they’re not where everyone says they are.

I’ve never had a therapist break confidentiality, but I know several people who have, and their therapists are still practicing. The existence of widely cited rules does not, in itself, cause those rules to be followed. Rules aren’t magic.

And then there’s the thing where, it’s not breaking confidentiality exactly, but they make helping you contingent on you agreeing to let them discuss things with someone else. (eg: a disability support professional, your medical doctor, a parent, etc).