Devon and Cornwall Police quizzed almost 20 people over their plans to protest while the Olympic torch relay was making its way through the two counties.
The force confirmed in a Freedom of Information Act response to the civil liberties campaign group Big Brother Watch that it had "visited or spoken to" 18 people ahead of the arrival of the torch in Cornwall on May 18.
The force said: "Devon and Cornwall Police engaged with individuals in order to ensure that their right to protest was enabled without disruption to any other legitimate activity.
"I can confirm that 18 people were visited or spoken to in relation to the policing of the Olympic torch relay through Devon and Cornwall, in order to ensure that the force could support its obligations in relation to the facilitation of peaceful protest as well as the safety and security of the Olympic torch and bearers."
After a positive response from Devon and Cornwall, the campaign group followed up by asking other forces if they had done likewise.
However it has accused forces of a "cover up" about Olympic policing after the requests were rebuffed.
It said 13 forces had replied, with all but one using a template that claims confirming the visits have taken place would aid terrorists and undermine protecting "future Olympic torch relays which may pass through the UK".
Nick Pickles, director of Big Brother Watch, said: "The fact that police forces are devoting resources to pre-crime investigations about the Olympic torch relay demonstrates how utterly out of proportion the Olympic security operation has become.
"Rather than investigating crimes that have actually happened, the police are wasting their time questioning people about a potential protest and social media postings, neither of which is a crime or a security risk.
"To now try and cover-up what has happened by claiming it would aid terrorists to confirm they have visited people is utterly ridiculous."
The template response states that "the release of information identifying the focus of policing activity in safeguarding public order and the prevention of terrorism could be used to the advantage of terrorists or criminal organisations".
The response also states: "To disclose intelligence, tactics and methods used to ensure the safety and security of the Olympic torch relay may make them ineffectual for future similar events and future Olympic torch relays which may pass through the United Kingdom."
Among the forces who have used the template are Avon and Somerset, Surrey, Cambridgeshire, Gwent and West Mercia.
The torch, which has visited more than 1,000 communities throughout the UK and has been carried by more than 7,000 torch bearers, arrived in London at the weekend. Its journey ends on Friday, the day of the Olympic opening ceremony.