reminding people that opening their WiFi is the socially responsible thing to do
No, it is not. This is like saying it's socially responsible to leave your keys in the ignition so your neighbors can barrow your car when they need to run to the store.
It's not socially responsible to suggest that it's OK for people to use Internet connectivity they don't know anything about, like who the man in the middle might be. It's not socially responsible to allow unknown third parties to rile though your personal belongings, like those tax returns you left on that unsecured windows share.
Finally, "legal protections" are for people who can afford lawyers.