Pressure group the Confederation of British Industry (CBI) has hit out at 'warchalking' - street markings used to indicate the presence of wireless networks.
Geeks have begun to draw symbols on walls and pavements to mark points where signals from nearby office wireless networks can be tapped into to access the internet.
"The CBI condemns warchalking as an implicit incitement to irresponsible and illegal acts," said Jeremy Beale, the CBI's head of ebusiness.
Although warchalking began as a scheme designed to let people with laptops share internet access that already exists, the CBI is concerned about potential security risks.
"Hacking company networks could potentially provide access to commercially sensitive data and is a security risk," Beale said.
"Warchalking could harm businesses financially and operationally, while also compromising the confidentiality of customer information," he added.
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