The payload transmitted over open Wi-Fi networks are also only accessible with some difficulty, the judges noted in their ruling. "Intercepting and decoding payload data communicated on a Wi-Fi network requires sophisticated hardware and software," the judges noted.
Wi-Fi transmissions are not readily accessible to the general public also because the general public lacks the expertise to intercept and decode Wi-Fi traffic.
"Even if it is commonplace for members of the general public to connect to a neighbor's unencrypted Wi-Fi network, members of the general public do not typically mistakenly intercept, store and decode [data transmitted by others on the network.]"
Critical of ruling
Daniel Oliver, a senior analyst with the Information Technology and Innovation Foundation (ITIF), called the Court's ruling unpersuasive and flawed.
Intercepting unprotected wireless traffic these days is no more difficult than intercepting CB radio transmissions were in the past, he said. So to maintain that the same exemption that is available for unprotected radio transmissions is not available for unprotected Wi-Fi transmissions is unfair, he said.
"It's the first time the Wiretap Act has been interpreted this way," Oliver said. "The Wiretap Act says you can't eavesdrop or tap into a conversation. But if the communications is not protected, then it is clearly not a wiretap.If you are broadcasting your message in the clear and if somebody else receives that message, it is not their fault [for receiving it]."
The court's interpretation that the Wiretap Act exemptions are available specifically for radio communications, but not wireless communications, also violates technology neutrality, Oliver said. Neutrality requires that the law neither favor or discriminates against a technology and instead treats them equally, he said.
When Google first admitted that it had been inadvertently harvesting Wi-Fi data, dozens of state Attorneys General had indicated they might take legal action against the company, Oliver noted. The fact that none of the them did shows that they did not believe the company had violated wiretaps laws, he said.
In its opinion, the court noted on several occasions that the Wiretap Law makes no reference to Wi-Fi communications. Oliver said Congress should consider clarifying the Wiretap Act to ensure that data sent unencrypted over a wireless network does not have an expectation of privacy.
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