The three former children's laureates who have kicked off the growing debate about vetting those who come into contact with schools and young people have done a great thing. They have questioned robustly and independently the growing apparatus of vetting, surveillance and checking that the government has set up and is feeding.

From October 11.3 million people who work, however tangentially, with children in health, education and care must be registered and must pay £64 for the checking procedure. (Netting the state £704m – can it cost that much to maintain?) Beatrix Campbell writes that we should be "glad" to do this if it means that it signals to young people that the "school thinks their bodily integrity matters ... more than a minor interruption of adults' privacy".

There is quite a lot wrong with this statement. No one can be glad that the right to privacy is eroded. And there are quite a lot of vital "signals" to young people that will also be eroded by developments in child protection. (This went into overdrive after the terrible Soham murders. A key fact there – nothing to do with general surveillance – was that Huntley's references, which would have uncovered a previous incident of child abuse, were not fully checked by the school.)

A vital part of education is that children should have as much exposure to different worlds of art, music, sport, nature, work and outdoor adventure, as possible. A lumbering apparatus of checking is going to make this less rather than more likely.

At English PEN we've been working in schools for over 10 years, putting writers in to work with children, introducing them to their work and to the idea of writing themselves. Without exception the visits of these writers have been attended by numerous adults, in a public space, with no time or need or request for any private time between the writers and the students. We trust the schools to provide some of the right ingredients for a successful visit – they trust us to provide a good author who will treat the event as a unique opportunity for children to think and talk about writing, reading and aspects of life in general.

The signal to children that the public space is to be defined as a potentially dangerous space – where the values of the worlds where the visitors work, whether it's in writing or engineering or family, are secondary to the definition of the adult as "vetted" or "safe" – is limiting and fearful. We are creating paranoia .

Is this vetting useful? It seems a wholly disproportionate demand to make of writers and other people who want to go into schools on an occasional basis, to public talks or demonstrations. The laureates agree that those who work habitually and in close contact with individual children should be checked. Of course.

But this extra layer of bureaucracy and intrusion – and the peculiar subliminal message that all adults are guilty until rendered innocent by check-up – will certainly stop both schools and visitors from the outside world from making the considerable effort to create the kind of magical encounter that a visit can be.

This would not be a signal, this would be a dreadful deprivation. The authors have raised powerful principles here – of trust, of proportion, of the most important elements in a child's education, of the respect that we need to maintain for a good society. The government's anxiety about child protection should not lead to depriving schools of writers and other potential visitors and mentors who believe the vetting and barring scheme is disproportionate in its effect.