Yes, there is a point where it goes from healthy interest to unhealthy controlling obsession. There are a good number of mothers like this at the school, but there are also a good number of mothers who have a healthy level of interest in our children and none of us like the atmosphere that is created by the former. They act like they own the school and really do very little to improve it...They are supposed to be busy with volunteer work, but mostly you'll catch them gossiping about teachers, students, etc. They all claim to have profoundly gifted kids of course according to some test somewhere and sometimes the kids are embarrassed by the fact that mom is always around. I do think the faculty gets worn down by these women due to sheer persistence. I do see their kids quite frequently as they are in the same social group as mine and I would know if they are profoundly gifted and they aren't. Often times they have a bully style personality that they get from mom. I do think that the school ultimately needs to put their foot down with regard to this 'helicopter' parenting, but being the first to voice this will ruffle feathers..I know for a fact that many other moms feel as I do, but just don't want to do anything about it.
That being said, you seem to have a lot of anger towards your children's school (btdt by the way and it is not healthy for anyone) and your children are unhappy at the school - perhaps a change is in order. Are there other schools availible? Homeschooling?
If there is a strong culture of heavy volunteering plus the children of volunteers having "perks" that is unlikely to change in a timely manner.