For PG, I personally have not yet seen it work well in our school system at all (but we have a very different system here and I am only going of the handful of PG kids I know from trying to source them as peers for dd).
That is what the parents of the two PG kids I met here said. They home-school and send them to community college and keep them in public for social reasons.
I know of two other PG kids from friend's kids at local privates as well. They are subject accelerated 4+ years. The latter seem to be found in 1 out of every four grades. The privates seem to be very attuned to what these kids look like.
As for tutoring. That is going on here in some communities and skews the results on many standardized tests. A psych friend has seen kids showing up 100% prepped for some IQ tests. A lot of privates now have their own tests they give as well. It screens out most of the tutored kids.
Your comment about changing the problem to a verbal one requiring coding and problem set up is astute.
As for teachers. Here is what I have found.
Most have teaching degrees and are not equipped to deal with a PG kid once the kids start getting into HS or college level math/science. If the best math teacher at the school does not have a math degree then they will not be able to teach much beyond Algebra I at the level a PG kid needs. From there, they need a teacher with a hard degree and graduate level experience.
