"And that’s just one kind of Wi-Fi-based attack. It gets
worse. When you connect over Wi-Fi, a lot of relatively sensitive
information (e.g., passwords, session IDs, cookies) is routinely
passed unencrypted and is thus open to being trivially sniffed by
anyone else on the same Wi-Fi site. That person sitting next to you
in the coffee shop could well be running a sniffing tool like
Wireshark and collecting anything sensitive that your browser or
email client emits."