bluebicycle!
Yes, that's obnoxious. You absolutely can -- and should-- point their inappropriate volume to them. Surely others have this problem with them as well. As notz pointed out, it's their professional duty, and it seems they need to be reminded of this. Chances are pretty high that they have one of those "please wait here for customer privacy" kind of signs on a stand. I'd be tempted to step back, grab it by the post and tilt it while gesturing "Carol Merrill style", with a questioning "hello??!!" expression. Then again, I'm a smart azz

The inappropriate incident that stands out the most for me was regarding Lamictal. Nowhere does it indicate what it's being prescribed for. One time, apropos of absolutely nothing, in the midst of ringing me out at the register, a tech asked "so how is this working for your headaches?" I just glared at her. Fishing much? WTF?!

(Strangely, it's sometimes prescribed off-label for them. But that's hardly the point.)