In general, I'd say that teachers are not very good at identifying who is and isn't the "really gifted" among their students. Teachers, and this is a generalization, tend to view the most compliant, convergent, high achieving kids as the most gifted when they may not be gifted at all but rather simply high achievers who fit the bill of what school has to offer.
We were taught (in my EA program) that teachers are correct only 50% of the time but parents are correct 80% of the time. Kids who achieve well and behave themselves in a regular class are one who are having their needs met and therefor are likely bright, or less gifted than the kids with the bad marks and behaviour problems... many teachers don't understand this though and miss it entirely.
