Here in my neck of the woods, that's basically what's happening by default.

A year ago, most of the neighborhood's WiFi networks were open and unprotected and, mostly, broadcasting their out-of-the-box SSID.

Now, 10 out of 12 have security on. And because 8 of these have distinctive names as assigned by Verizon FIOS, I surmise they have the WEP key stamped on their router.

(Of course, there is one other factor; Verizon requires that its technician do the install, so you have somebody turning on the security and getting the household's computers to connect to the network who has some idea of how to get it to work.)