The reservations have emerged in responses to the implementation of the Protection of Vulnerable Groups Act, which the Scottish Government has just published on its website. Small groups which rely on informal voluntary help are particularly worried, believing they could be overwhelmed by unnecessary bureaucracy.
The Government wants a new registration system which removes the need for multiple checks, a cause of frustration with current disclosure procedures. Instead, records would be updated automatically when circumstances alter, such as when people change job or are convicted of a crime.
But critics believe proposals focus too much on background checks of vast numbers of people, rather than on training to spot suspicious behaviour in the first place.
The Scottish Parent Teacher Council called for a "more commonsense understanding of what constitutes childcare".
In its official response to the consultation, the council stated: "The current definition of childcare is too wide. It even protects buildings - educational establishments - when no children are present."
The SPTC is also bemused by the suggestion that anyone receiving healthcare might be deemed "vulnerable". It added: "The definition is too wide and will catch all manner of folk who are not, in a commonly understood way, vulnerable."
The council was concerned about the demands of detailed record-keeping: "Small voluntary groups, such as parents' organisations, do not hold records on folk who offer to help. They do not have the capacity to hold such records; they do not have anyone who is able to be responsible for such records."
The Scottish Sports Association fears a move towards mandatory disclosure checks of all sports coaches and the majority of other volunteers at clubs, and urged the Government to avoid such a scenario.
"The administrative resource implications for sport and other relevant authorities are huge and appear to be out of all proportion to the potential protective benefits of such a move," it stated.
The sports body is "extremely concerned" that the proposals will lead to "a highly bureaucratic scheme which will do little to provide real additional protection".
It calls instead for a better educated workforce more able to pick up on warning signs, such as when a child is unusually withdrawn or leaves a club without explanation.
"If the new scheme is introduced without significant additional investment in training for volunteers and staff in sport, we fear it will make little impact on the day-to-day protection of vulnerable people," the association states.
Similarly, Lothian Association of Youth Clubs is concerned that the consultation focused too much on the minutiae of criminal record-checking systems, which could actually be a distraction from protecting children.
Some organisations were more relaxed about the proposals. Scottish Bowls Coaching, which works with people who are blind, deaf or disabled, said guidance on working with children "does not give us any problems and is entirely accepted throughout our organisation".
A spokesman for the Scottish Government said: "None of these proposals is final. This is a consultation process where we invite views to help us shape legislation, and any concerns raised will be taken into account. The safety of children and vulnerable groups is paramount and that is why we are committed to developing a robust, strengthened and streamlined vetting and barring scheme to keep those who would do them harm out of relevant employment positions."
The Protection of Vulnerable Groups Act 2007 was a response to the main recommendation of the Bichard Inquiry report following the Soham murders in 2002. It called for a registration system for all those who work with children and protected adults.
A report on consultation responses will be published later this year and the new scheme is likely to come into force in 2009.
The Scottish Artists Union's most serious worry is that its members, which it describes as being in the lowest income group in society, will have to pay upwards of pound;150 a year as they move from project to project and are required to be vetted each time.
"An artist's practice is unlikely to earn them more than pound;4,000 in the same year. As the bulk of that money will go back into the practice to cover material costs, this is an unacceptable added barrier to earning," the union stated.
There is potential confusion over definitions of a child (under 18) and a protected adult (over 16), according to Youth Scotland.
The Scout Association is worried that a system of retrospective checks would cause "great administrative difficulty", as its adult membership in Scotland numbers 8,000.
Chess Scotland fears the definition of a protected adult is "far too wide" and will include "most of the population of Scotland".
The Girl Crusaders' Union is unimpressed with the "confusing" language used in guidelines, and calls for the use of plain English.