I have been thinking about this but as someone who never knew, and whose children are unlikely to be tested, I didn't feel i had much to add. But what struck me as I read through the comments was that it doesn't seem to be the knowing or not knowing that causes the problem, but the who context that goes with it.
In my case, I don't know my IQ because I don't think I was ever tested. My family thought it was 'just smart' so it was all supposed to be about academics. So not knowing my score was a problem for me because I never knew that my IQ might be contributing to personality or social interactions. I wish we had known, and occasionally toy with the idea of getting tested so I don't keep thinking I'm just pretending to be gifted, lol. But that isn't just knowing the actual number, I suppose, it is more that I wish I and my parents had known more about gifted children.
A PP talked about the girl who knew her score and it was a burden because of pressure from her parents, but IMHO it isn't the knowing the score that was the problem, it was the way the score was being used. So even if she hadn't known the exact figure, the pressure would still be there.
I'm not sure this answers the question either way, but I think it is worth taking into account the whole situation, not just knowing or not knowing a number.
