At least two dozen schools have forged ahead with ballots despite a possible change of government and the threat of Labour ditching the Tories' opting out policy.
Some schools are yet to even start balloting and are due to announce results after the general election.
The next education secretary's in-tray will contain 13 applications from schools where parents have voted in favour of opting out and governors have formally published proposals. Parents in a further eight have voted in favour of going grant-maintained.
Eight more schools are holding ballots currently or are due to start polling very soon.
At Potterne Church of England primary school in Devizes, Wiltshire, ballot forms are set to be sent out just three days before the May 1 election.
Labour education spokesman David Blunkett's office this week stressed that each case would have to be looked at "on its merits" under the existing legislation until laws were brought in to create a new school framework. Foundation schools will most closely reflect the way GM schools are managed, but they will lose funding advantages and be forced to accept two local authority representatives on their governing body.
Mr Blunkett's spokesman said: "Our goal is to have a system as set out in our manifesto but while this is getting underway the secretary of state will have to consider each individual ballot on its merits. It would be a matter for the secretary of state under the existing legislation until we introduced our proposals."
Pauline Latham, chairman of the pro-opting out Grant Maintained Schools Advisory Committee, says any future Labour secretary of state ought to respect parents' wishes.
"If David Blunkett becomes secretary of state he should let these schools go ahead and opt out," she said. "He can't leave them in limbo until he changes the legislation."
Jim O'Donnell, Labour-appointed chair of the governors at the 300-pupil St Thomas of Canterbury Roman Catholic primary school in Gillingham, Kent, where results of a ballot are due out on Tuesday, admitted he had no idea what would happen if the vote is for opting out and his party wins.
"It would present us all with a headache," he said. "I've had discussions with various people and there are a number of scenarios. If the parents decide by a majority that the school should opt out then I and the other governors will respect that decision. But I don't know what a Labour government would do."
Labour's manifesto says grant-maintained schools would be allowed to prosper."Tory claims that Labour will close these schools are false," it says.
Mrs Latham says the current rash of schools holding ballots contrasts with the lull before the last election.
"In the last election, people believed GM schools would be scrapped if Labour got in," she said. "But many parents don't really believe that will happen this time."