> Should what the outside of your house look like be private information?
Everyone knows that someone can record the outside of your house; not everyone knows that SSIDs with location can (and actually are!) registered. Do you notice the difference? You can't assume that WLAN specifics are as tacit as knowing that people can look at my house!
Even if you did explain to everyone that their SSIDs are being indexed - what would you tell them is actually being indexed? What personal information are they giving up? Your address, age, other residents of your house are already listed publicly. The name you gave your wireless network pales in comparison.
Everyone knows that someone can record the outside of your house; not everyone knows that SSIDs with location can (and actually are!) registered. Do you notice the difference? You can't assume that WLAN specifics are as tacit as knowing that people can look at my house!