I have no first hand information. The internet tells me via google that Pine View school only teaches one grade ahead of the rest of the schools.
http://www.greatschools.org/florida/osprey/6633-Pine-View-School/This article online is bathmouthing them, and it's the first time I've heard of the school. They say only 2.2% of the students in the world score the cut off scores for the school, but
in Sarasota County, 5.2% of students meet this standard, or more than twice what is statistically expected.

of certain types of families

. It could be sour grapes or the Lake Woebegone effect, or pilgrimages looking for the greener pastures. (see link below)
http://www.yourobserver.com/news/sa...y-View-Pine-View-School-gifted-or-gildedIf you look at the comments in that link you'll see a Pine View parent saying that it is a rigorous program that it's easier to get into Pine View than to stay in Pine View, so, if you're fudging to get in you'll be struggling. But that first link from Great Schools explains the school teaches just one year ahead. That might or might not be enough. Their selling point is the culture of excellence, that it's ok to be "the smart kid". They also produce National Merit Scholars which is the quality seal of a good school.
The statistical anomaly is created by the many families that relocate to enroll their students at Pine View School. With 25 National Merit Scholarship semi-finalists and a 1968 average SAT score (which significantly exceeds the scores of all other public schools in the state), Pine View is an academic powerhouse and a major draw for those seeking the Florida lifestyle. While attending the open house for new families, we toured the school with a group of parents who had overwhelmingly relocated to Sarasota from as far as Connecticut and Arizona so that their children could enroll. In fact, we were the only Floridians in the group. Pine View School provides a wonderful resource for the residents of Sarasota while attracting many new families, businesses, and yes, intellectually gifted children to our fine community.
so, there's your answer- it's easier to get in than stay in that school. the second link has a lot of comments from PineView students and parents.