I am disappointed to say that the post has now been removed, so either someone became abusive or the instigator of the discussion withdrew the post, maybe because it was too controversial. So I have to try and reconstruct it from memory rather that actual postings but it went somehow like this.
My reply to the first question was that it was fine and that the child could simply be thought of as working at an advanced level. Not "missing a year or two". Other contributors came into the discussions and said that the child would probably be too immature to be able to cope at the next level(s). They said there would or could be an emotional and social toll on the child and that a number of factors needed to be considered like friends at that level.
I suggested that grouping all students together, based on their age, was an artificial concept anyway (arising from the industrial model that Sir Kenneth Robinson talks about in this video. We are still educating children in batches. (Check it out around the 6 minute mark). The most important thing about kids is NOT how old they are. Sir Ken is saying it is time to change the paradigm and I agree.
The question to me is about should the child work at the same level as their age counterparts or should they work at the level which extends their intellectual capacity? A modern learning environment, MLE or ILE, should allow students of different ages to work together - emotionally or socially disparate they may be.
I so wish the conversation could have continued. I am very interested in what others think.