LOL! Connecting to an open wi-fi is not "sniffing the packet streams." I'm not sure that you even know what you are talking about at this point.
I've posted links to the some of the relevant FCC regulations. I'm familiar with the legal constraints as I have both an FCC First Class Radiotelephone license and an Extra Class amateur radio license. Certifying that a device meets FCC specs before going on the air includes signing my name and license number. I've also been building computer systems since 1980...including security. While employed at the phone company, I had to sign an affidavit concerning privacy of communications annually. The relevant sections of the Communications Act of 1934 were excerpted regarding interception of communications and the penalties for divulging the information.
What's your relevant experience on the topic?