UGH! I once had a physician shame me for wanting to have an "alone talk" when my eldest started tic'ing like crazy and I didn't want to scare him. I don't remember what he said, exactly, but it was something like "I think it will be more traumatic to leave him in the waiting room." In retrospect, tics weren't as scary as I thought they *might* be (at that time, I had no experience and the internet was not very much fun--1996-ish?)
I think it's absurd to not be able to have a candid discussion with a provider, out of earshot. In my professional life, it's extremely uncomfortable when adults "overshare" in the presence of their children. Little pitchers/big ears.