Children have always called me by my first name and I'm fine with it.
I don't think being made to address adults as Mr/Ms So-and-So makes children respect that adult any more than if they used the adults' first names. I know there were adults I addressed "respectfully" as a child whom I thought were stupid and/or bullies etc.
@Sharon: Adults can make children display all the outward demonstrations of "respect" they want. But deep inside, children feel the way they feel. Little girls used to be expected to curtsy to their elders back in my grandmothers' time, but I doubt if that made them feel any more "respectful" inside than if they hadn't been required to do so.
When I was a kid, adults who demanded that I address them as "sir" or "ma'am," (which I wasn't required to do with my parents), just seemed like bullies. It didn't make me "respect" them more.
@Badseed exactly but most people especially those higher on the narcissistic spectrum, don't care so much about how things are, only how they look like they are.