Universities, libraries and Wi-Fi providers such as cafes, caravan parks and hotels may have to register as internet service providers to conform with proposals in the Digital Economy Bill, adding to their operating costs and obliging them to police their networks for illegal file sharing.
A clarification note issued by business minister Lord Young in response to questions in the House of Lords, where the bill is being reviewed, said it was "critical" in terms of the bill whether the entities were ISPs or subscribers.
Where they were defined as ISPs, they would have to comply with ISP obligations, provided the level of infringement on their network was such as to breach any threshold limit set out in the code.
If they were subscribers, they could receive and have to act on notices from their ISP to take down offending material. If they did not act, they might be blacklisted and their access to the internet blocked.
Appeals would be heard by "the appeals body", the note said.
"Our intention is that the code should require ISPs to provide generic advice and information on how to tackle (copyright) infringement as well as how to protect a wireless connection/network, and that such advice is appropriate for the type of establishment in question," Young wrote.
"We will add a requirement in the bill under clause 8 that this is a provision that the code must include."
Jim Killock, spokesman for the Open Rights Group, said: "This bill is going to make life very difficult for a very wide range of users. the government's notes admit as much."