The distinguishing feature is that you believe strongly in educational principles - in my case anti-sexism, anti-racism, equal opps for kids with special needs - but you shrink from raising any concerns with your own school. My own achievement so far has been a politely-squeaked request to have the school uniform exchange held occasionally out of school hours so that working mothers can use it.
Is this caused by fear of personal conflict, or fear of being seen as a boring old nuisance (or even a Parent from Hell), or lack of energy to follow through what one starts - or all three? I do know it is not good enough.
In the meantime, my whizzo idea is for an exchange scheme among like-minded parents. We lefties could start campaigns in each other's schools, and write stirring letters to heidies several miles away: "I am extremely disappointed at your failure to celebrate multicultural festivals in this school."
Meanwhile the 3Rs brigade would demand in purple ink: "Do you seriously consider drawing pictures of granny to be homework?" Seriously, I think the climate of media ridicule about "political correctness" is intimidating too. And it's easy to find gift targets from thousands of miles away - such as the six-year-old American boy over-punished for "sexual harassment".
What's important is not "correctness" but things that make children feel hurt and humiliated, and we have to keep politely insisting on that.
Going against the grain of what most people want for their children can make you feel a real oddball. One academic friend spent months combing Edinburgh for a suitable school for her five-year-old. Most people she knew were looking for uniform, discipline, lots of homework and, well, not too many working class and ethnic minorities - she sought the opposite on every count. They kept recommending "good" schools, and she never did dare confess how bizarre her ideas were. But this search is a cop-out - you have to start where your child is, and work for change.
Hot on the heels of my resignation from the Labour Party, my daughter and I enjoyed the last Fettes Open Day - especially spotting all those parents from my child's primary school surreptitiously casing the joint. We were only there from insatiable, morbid curiosity and a last desperate attempt to understand former pupil Tony Blair. Of course, that's what they said too.
Unfortunately, my gutter-spoken kid was so riveted by the kilts, dorms, microwaves, washing machines and sophisticated kindly pupil guides in the girls' house that her only desire was to sign up immediately.
What a relief one of the few policies which that nice Mr Blair hasn't ditched is abolition of the assisted places scheme. If my socialist ideals continue to make such pathetic impact on my own flesh and blood, at least I can use that as an excuse.