I, too, see a lot of high achieving good students being considered gifted by both their schools and their parents and would be hesistant to agree that parents (or schools) are good, let alone excellent, at recognizing giftedness. I'm also not sure on some of the characteristics on the GDC checklist, honestly.

Yes, it is probably accurate to say that many, or even most, gifted kids are intense and sensitive, for instance. Does the reverse hold true? Are many, or most, intense or sensitive kids gifted? It's like a rectangle/square thing -- all squares are rectangles, but all rectangles aren't squares. I'm not comfortable with having parents fill out checklists stating that their kids are sensitive and using that to assume that the child is also gifted. I know plenty of highly sensitive children and children who meet other objective measures of personality who are not gifted.