But privacy laws were not crafted to cover scenarios where the owner of the data -- in the Firesheep example, people accessing their Facebook accounts at an unsecured hot spot -- didn't take steps to protect their information.
That's one of the reasons why the legality of Firesheep, and other tools like it, remains up in the air.
"It's an unsettled legal issue, but it will be tested at some point," Christie said. "Like many other situations, this is one of those areas where the law was crafted prior to the Internet age, and the courts will have to catch up."
Gordon agreed. "It may be difficult [to clarify this], but it will happen," he said.
Another law may also apply to Firesheep use, said Malone. That law, the Pen Register and Trap and Trace Devices Act (sometimes shortened to the Pen/Trap Act), was crafted with telephone line wiretapping in mind, but it could be called on by prosecutors, Malone said.
A packet-sniffer that snatches important information, such as the IP address or other sending and receiving information, including addressing or routing data, is one case where the Pen/Trap Act might be applied.
"If something like Firesheep grabbed some pretty bad stuff, technically it may have violated [the Pen/Trap Act]," said Malone, adding that an aggressive prosecutor might decide to file charges based on that law.
Christie wasn't so sure. "If a tool like Firesheep captured IP addresses, the criminal component of it might apply, but I'm not sure anyone would use it."
The legal experts also noted similarities between the Firesheep situation and Google's trouble with U.S. and foreign regulators over its Street View vehicles. Earlier this year, Google admitted that those vehicles had grabbed information from unsecured wireless networks as they snapped photos and mapped hot spots.
Two weeks ago, Google admitted that in some cases the Street View sniffers had captured complete e-mail messages and user passwords.
Google claimed that the data collection had been unintentional, and it argued that the practice did not violate federal laws because the wireless networks were not password-protected. However, that didn't stop several state attorneys general from asking Google for more information as they tried to decide whether the company broke federal or state laws, including wiretapping and privacy statutes.
Last week, the Federal Trade Commission closed an investigation into Google's Street View activities. However, the company faces numerous class-action lawsuits in the U.S. over the practice and may be fined by some European privacy agencies.
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