The Harman episode has highlighted Labour's dilemma in devising a policy that offers choice to parents without creating a pecking order of schools. The strategy as envisaged in the policy document Diversity and Excellence is that parents of children in the primary feeder schools of grammar schools could be balloted on the question of whether selection should be ended.
It would appear that the local education authority gets the difficult task of deciding which primary schools need to be consulted - grammar schools often draw their pupils from a wide area.
But this is a minor problem compared with Labour's task of devising admission policies that appeal to South-east middle-class voters, who it wants to win over.
Labour insists that schools will not be able to select on the basis of academic ability, but its policy document seems to suggest specialist schools can select on aptitude. It says: "Expressed preference by parents will always take into account the specialism and expertise that exists in a school where a child has a particular aptitude. So long as this does not exclude or deny equal opportunities, we would see this as an acceptable part of an agreed admissions policy."
There is a view among academics that there are no reliable tests for aptitude, and so-called aptitude tests are tests of general ability.
Overall, the paper suggests that Labour lacks a strategy for ensuring secondary schools have a comprehensive intake.
In most schools, the local authority will set the admissions policy. But when it comes to church and foundation schools (a new category expected to attract former grant-maintained schools), the governors will decide the policy, though it will have to be agreed with the local authority. If schools and councils disagree, Labour intends to allow appeals to an independent body.
The paper does offer suggestions for the basis of selection with priority to siblings and to those that live closest, methods currently used by most schools. In addition, David Blunkett, the party's education spokesman, has promised a ban on schools using "covert" selection by interviewing pupils and parents.
The present policy will do little to hamper middle-class parents using the system in a similar way to Ms Harman to ensure their child gets a place in a school with better than average results.
As Ms Harman points out in the Guardian this week, she and her family could have moved out of her constituency to be close to high-performing schools, a common practice among aspiring parents, but only available to the affluent.
In her defence, Ms Harman says she was prepared to use the existing system to to make a decision in the best interests of her child.
"People accuse me of being a hypocrite or of operating double standards. But Labour did not create the system in which we as parents are making our choice."
While St Olave's in Orpington is a grammar school, Ms Harman insists she does not favour selection. She would prefer to see it ended at the school, but accepts that decision had to be taken by the parents.
She also maintains the decision does not mean she is out of line with Labour's education policy.
She says: "Nothing I have done leaves me out of line with Labour education policy. Nor should it be seen as a stalking horse for a policy change. It is about our making a decision as parents for our children."