This guys comment was that if they know that hey are 'G and T' it can have a detrimental effect on them if they try to do something and fail. Often children will then move away from the topic, as G and T children they feel they cannot 'fail' at something, so the something is avoided.
I have to say this this is my experience of working with quite a lot of G and T children.
He felt that G and T groups were not the way forward and that children would be better being stretched inside the classroom with their peers. I can personally argue this one either way, but if it is to happen in class we probably need time to prepare resources etc.
My feeling is that many registers are missing the very children that it is most meant to support....the bright children of more deprived families.
many of the tests for G and Tness are based on vocabulary, and are such tend to be biased in favour of middle class children. and the middle class children tend to be the ones who can be more easily stimulated at home, since it is more likely to have access to the internet and lots of books.
My experience of G and T schemes (and I've been involved in a few as a teacher) is that they are very often divisive, mostly ineffectual, and very often miss the kids who need them most. The scheme is a classic case of 'We need to do something, this is something, we'll do this'