I don't agree intent has any relevance here vs the other issues at hand, and it is news to me that there is some actual distinct expectation of privacy with regards to wavelength as you state.
Visible and IR wavelengths don't reach outside through non-windows, because of physics - but I don't think there is any inherent expectation of privacy - quite the opposite. If you leave your front bay window open and people outside can see in, and you call the police for privacy invasion they will laugh in your face in most places - in fact if you are doing something deemed obscene or distasteful you may be the one arrested - and for good reason. They'll tell you to get something to block the light like a curtain.
Whether or not people intend it - wifi signals easily will make it to the street - and they're on shared spectrum. Especially if you're going to pollute the public ISM band - it's sort of on you to take whatever precautions you need to stay safe whether that is better encryption, a faraday cage or just abstaining and finding alternative means.
If you start blasting loud noises 24/7 constantly in your neighborhood and someone complains, is your response going to be well, "I don't intend for this garbage to reach my neighbors"?