"Just because Wi-Fi is free to the user, it doesn't have to be sort of a free-for-all anonymous, irresponsible service," said MacKinnon. Many big chains , such as Starbucks, do so via user accounts, he noted.

"It seems to me sort of strange that when it comes to Wi-Fi, people feel that Wi-Fi should not be managed by account. I think it's just because the culture preceded the capability," said MacKinnon. "Increasingly, people realize that if they try to create mischief from home or work, it's too easily traced to them, so their first thought is [to] go and use Wi-Fi in public. ... Unfortunately, that takes advantage of the businesses that are providing the free Wi-Fi."

Austin Wireless provides hot-spot authentication services to the city of Austin as well as commercial hot spots, which include a minimal registration -- a username and e-mail address -- and an agreement to terms of service. The service costs hot spots US$10 per month on top of broadband charges and does not track which Web sites users visit. MacKinnon calls it "a service which is discouraging abuse on a network, which probably costs more than $10 a month to cope with."

If someone uses a hot spot for illegal activities, he isn't necessarily putting the hot-spot operator under any legal risk, said Bart Lazar, an intellectual property attorney at Seyfarth Shaw LLP in Chicago. Contributing liability, which involves aiding and abetting criminal conduct, occurs only if you know the conduct is taking place, said Lazar. That liability, for instance, might be used against a technology developer that builds something designed to circumvent a protection.

"Internet Explorer has the capability to engage in copyright infringement, but it's not the fact that the tool can be used to engage in the infringement that is the issue," said Lazar. It's whether the tool was design for the purpose of infringing on copyrighted material, for example, he said.