Now that I think about it, and I have literally never considered it before, most of the conversations I have had with adults about being young for grade have started with my child's Grade skip... I just don't mention it to most people. So all of these people would have been friends or people I felt comfortable discussing it with, possibly including parents of the child's friend in birthday party scenarios.

"Oh they're skipped? Won't they finish school really young? Are you worried about that?"

"Well actually I was slightly younger than they will be when I finished school, because of the school start thing..."

"Oh, right... Oh, did you do the school start thing? I did that too. How old were you when you finished? Oh! I was even younger than you when I finished school!..... I guess they will be fine then, we were fine!"

And as I further consider this, 40 years ago they probably allowed more discretion to teachers about whether children who were SUPPOSED to do 4 or 5 terms did only 1 or 2. So most of these people, all of the ones I can remember clearly discussing this with, are clearly intelligent and now highly educated and employed. They probably WERE somewhat deliberately "skipped" but in a very informal "the teacher sends them if they are ready" system that allowed kids who were "ready" to move on faster, while also being deeply scathing of acknowledging giftedness or allowing any other sort of accommodations.

How interesting this thought train has been.