Yes-- we are quite informal ourselves, but definitely encourage our DD to refer to adults with their proper titles unless specifically asked to do otherwise.

Particularly earned titles-- to which I include Dr. as well as Mom, Dad, and to some extent Mr. and Mrs. (because adults DO generally speaking have life experience, and she should respect that until she has reason to lose such respect).

It has been difficult for DD to refer to adults by their first names in professional/formal/educational settings. I also think that to some extent it is culturally insensitive for some Americans to insist upon it.

On the other hand, I've had difficulties with the school personnel on occasion because I would FAR prefer to be on a first-name basis with a 25yo teacher of my DD's rather than use titles... and honestly, no WAY am I going to be {Howler} while I stick with "Ms. Stickler" for the teacher. I did have a school administrator that didn't learn this lesson the easy way, however...

It's either first names or titles there. Mine isn't Mrs. Sorry. That's not an attempt to establish dominance, it's a matter of proper title. Like I said-- I think that first names is better between adults. LOL.

At any rate, some people are REALLY offended by not using titles. I consider this to be the equivalent of using informal forms of address in French or German-- sure, among peers it may be encouraged, and with close family, again, might be fine-- but generally in a professional setting it needs to be erring on the side of formality.

It just makes a better impression when you're dealing with the unknown when one defaults to the more formal means of address.
Schrödinger's cat walks into a bar. And doesn't.