the interception of communications sent over unencrypted Wi-Fi networks is permissible.
This runs contrary to the Google Streetview case from last year, where a judge was of the opinion that
While Plaintiffs plead that their networks, or electronic communications systems, were configured such that the general public may join the network and readily transmit electronic communications across that network to the Internet, Plaintiffs plead that the networks were themselves configured to render the data packets, or electronic communications, unreadable and inaccessible without the use of rare packet sniffing software; technology allegedly outside the purview of the general public. Thus, the Court finds that Plaintiffs plead facts sufficient to support a claim that the Wi-Fi networks were not "readily accessible to the general public" [...]
The judge in the current case did address the Google ruling, stating that
the proposition that Wi-Fi communications are accessible only with sophisticated technology breaks down. As mentioned above, Innovatio is intercepting Wi-Fi communications with a Riverbed AirPcap Nx packet capture adapter, which is available to the public for purchase for $698.00. [...] The software necessary to analyze the data that the packet capture adapters collect is available for down load for free. [...] With a packet capture adapter and the software, along with a basic laptop computer, any member of the general public within range of an unencrypted Wi-Fi network can begin intercepting communications sent on that network. [...] In light of the ease of "sniffing" Wi-Fi networks, the court concludes that the communications sent on an unencrypted Wi-Fi network are readily available to the general public.
The judge did point out, however, that the standards applicable to the two motions are different, which leads to contradicting decisions. For now, all we can say is that for the purposes of a motion to dismiss wiretapping charges, open wifis are NOT publicly accessible, whereas for a preliminary ruling on admissibility of evidence, it is.
Hopefully there will be a sensible final ruling at some point to make sense of this.