The other thing that you want to be aware of-- and we're in a small but high-achieving town with just two high schools, BOTH of which regularly produce NMSF's in fairly large numbers-- is that such proxies are often less about gifted children and more about ideally intelligent ones who have parents at the sweet spot in terms of support/push/expectations/involvement.
That can produce not only high achievement across a wide swathe of the student population... but also a LOT of helicopter/high-maintenance parents.
Unfortunately, if you have a kid who is the real deal (150+, not about 130 and ideally advantaged), you don't have a choice but to be an active advocate with the school to get basic educational needs sort of met... and if you're in a larger CROWD of parents making those phone calls, it is all too easy to get labeled "typical" parent who is after {insert topic du jour} for his/her special snowflake.
We've run into this the few times we've tried to do much of anything with our local schools. They have rigid rules intended to PREVENT parents from getting what our DD truly seems to need. If that makes sense. They actually mean well-- and a lot of it is intended to prevent parents from overzealously pushing their kids too hard. Which they do. The other thing that both of our local high schools are known for is not so awesome... mental health hospitalizations and suicides.
Lots of parents with terminal degrees, lots of bright kids, and lots of pressure can produce a profile of "high achievement" that it virtually indistinguishable from "loaded with MG+ kids."
