Kitty - these are some of the reasons why homeschool/unschooling is a least-worst situation for pg/hg kids. Schools are not always the best setting for them to thrive or be themselves.
With DS, he didn't need the school or teachers to point out his differentness. It was obvious as soon as he walked in a room or opened his gob. He had the perfectionism issue before he even started pre-k too.
DS didn't particularly like the attention of the 'stardom' from the teacher. It wasn't positive, far from it. When DS was 5, in pre-k, and in the pre-k/k/1st grade class , DS told the teacher that no one tells the [DS's name] what to do and that he didn't need her to learn. The teacher said that he was correct about not needing her to learn. She really didn't know how to respond to DS or what to do, which left us with a gaping hole.
Last year (at 6 and in k), DS didn't fare much better in a mixed aged setting with kids from pre-k to 8th grade. He didn't like being the 'mascot' by the older students and found it to be condescending. He also had a bully incident in school that wasn't pleasant either and remained awkward.
Then, there was the aspect of producing work in school and motivation. At the structured school, DS produced more but still underachieved. We didn't really have the grades and external motivation (ie. rewards/punishments) there much because DS was technically in pre-k. Still, it was there with punishments if DS didn't cooperate. At the unstructured school, DS underachieved and didn't do much work if it wasn't perfect. The teachers tried to motivate DS externally but this would often backfire. DS would then lose recess because he didn't cooperate or produce work. It was frustrating.
DS is very often not externally motivated, no matter how much you dangle a carrot in front of him. I guess I assumed that private gifted schools were somewhat knowledgeable about these matters and what to do. Unfortunately, that was a mistake and naive of me.
Between the teachers, other students, curriculum, etc. there's just so many variables that can make schools less than desirable and more of a hurdle, hindrance, and headache than a solution or answer. I'm not saying that schools can't provide for some pg/hg kids because I've heard tales on this board where it has been the case, but there's a lot of variables that can send a pg/hg kid sideways.