Parents are warning that new regulations for Scotland's police checks system will not only make it too expensive for councils to involve them in activities such as "paired reading", but will also "kill off" school exchange programmes that require host families.
The Scottish Parent Teacher Council (SPTC) has been one of the strongest critics of Government policy on disclosure checks.
Now, its new executive director, Eileen Prior, has taken up the cudgels from her predecessor, Judith Gillespie, and is warning that the pound;53 million it has cost the Scottish Government to develop the new checking system is completely disproportionate to the low numbers of people - "hundreds, not thousands" - who are on the list of adults deemed unfit to work with children.
The Scottish Parliament's education committee is currently scrutinising a number of statutory instruments related to the Protection of Vulnerable Groups Act. The regulations are widely expected to be passed, particularly as the Scottish legislation is linked to similar changes related to "vetting and barring" legislation being brought in elsewhere in the UK.
However, the SPTC, backed by Liz Smith, the Scottish Conservatives' education spokeswoman, has raised eleventh-hour warnings about the changes - particularly in relation to the impact of increased costs.
Under the new scheme, the cost of an enhanced disclosure - required by people working directly with children - has risen from pound;23 to pound;59.
The main benefit of the PVG (Protection of Vulnerable Groups) scheme, as it will be called, is that a disclosed person's record will be continuously updated. So once a person has been disclosure-checked, he or she becomes a member of the PVG scheme and can carry that membership to another job or position without having to apply for a new set of checks.
Adam Ingram, Minister for Children and Young People, told the education committee: "The pound;59 fee reflects the cost of maintaining a person's membership of the scheme throughout their working life. It does not reflect the cost of one transaction, as we have in the current system of disclosure applications, under which a search is done and a certificate is produced that reflects a snapshot in time."
But Mrs Prior warned that the involvement of parents in school activities such as "paired reading" schemes would be jeopardised by the significant increase in the charges which local authorities would have to bear.
She added: "We are concerned that the cost will be such that local authorities will say they are not going to pay for parents to come in. The cost has risen by more than 100 per cent and if local authorities and schools are looking at every penny - and they will be - that is going to be an issue."
Parents attending a parents' night at school will not have to be checked - as was originally feared - because they will not be in a "sustained, regular working relationship" with children. But it is likely that members of a parent council who run regular school discos will have to undergo police checks, although a last-minute volunteer would probably be considered exempt.
Mrs Prior has accused Scottish Government legislators of fudging the issue of disclosure checks for host parents by leaving it to individual local authorities' discretion. "This will have the effect of killing off the whole tradition of school exchangesstudent hosting," she claimed.
"They will either stop, or schools will simply start using hostels and boarding houses and so on. How this is meant to be safer for children, we have no idea, as people working in a hotel or hostel do not have to be checked."
Miss Smith, who is a member of the parliamentary education committee, said she feared that the new scheme would involve so much "red tape" that teachers would be put off running extra-curricular activities.
But Ken Cunningham, general secretary of School Leaders Scotland, said that as a former secondary headteacher, he was more comfortable with accommodating school parties in hostels or boarding houses because it was "easier to manage" than having children scattered around a number of family homes.